Academic literature on the topic 'Seedling age'
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Journal articles on the topic "Seedling age"
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Ekamawanti, Hanna Artuti, Lenawati Simanjuntak, and Abdurrani Muin. "Assessment of the Physical Quality of Eucalyptus pellita Seedlings from Shoot Cutting by Age Level." Jurnal Sylva Lestari 9, no. 2 (2021): 280. http://dx.doi.org/10.23960/jsl29280-290.
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The criteria for target seedling of Eucalyptus pellita F. Muell are at least 90days old, with consequences for the length of stay of the seedlings in the nursery. This study must assess the suitability as a target seedling first if it wants to plant the seedlings under 90days old in the field. The research aimed to evaluate and obtain the regression equation for the seedling’s age with the seedling’s morphological characters. The shoot seedlings cuttings aged 45, 60, 75, and 90 days after planting in the cocopeat growing medium were assessed. The study was used a survey method with a purposive sampling technique to obtain 60 samples by assessing the growth and appearances of the seedling. Furthermore, 15 samples were taken at random to determine the dry weight of the seedlings. Seedlings aged 75 and 90 days indicated the standard criteria as target seedlings for height, diameter, number of leaves, seedling’s health, shoot appearances, and seedling roots. The two seedlings’age levels have a sturdiness index of 8.34-9.78; shoot-root ratio 3.9-4.5; and seedling quality index (SQI) 0.22-0.23. Seedling age had a powerful positive correlation with the sturdiness index and SQI (r = 0.84 and r = 0.96). The regression equation of the sturdiness index is y = 0.048x + 5.435 (R2 = 0.996) and SQI is y = 0.004x - 0.064 (R2 = 0.926). This research implies that 75 and 90-days seedlings can be considered as one of the criteria for the age of E. pellita shoot cuttings as the target seedling in the SOP of PT. Finnantara Intiga.Keywords: cocopeat, Eucalyptus pellita, Seedling Quality index, shoot cuttings, target seedling
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Jellani, G., H. Ullah, M. Ali, TN Khan, MJ Atif, and M. Musa. "Impact of seedlings age on vegetable Marrow production." SAARC Journal of Agriculture 13, no. 1 (2015): 216–22. http://dx.doi.org/10.3329/sja.v13i1.24195.
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A study was conducted at the research field of Horticultural Research Institute, National Research Center (NARC), Islamabad, Pakistan during two consecutive years of 2011 and 2012 to compare the performance of seedlings raised in polythene bags with traditional direct seeding in respect of early harvesting and profitability. Seedlings of three different ages (40, 50 and 60 days old) of vegetable marrow were compared with traditional direct seeded crop. Transplanted seedlings of vegetable marrow produced fruits 36-38 days earlier and availability period of 34-38 days longer than direct seeded crop. Similarly, higher fruit plant-1, fruit weight plant-1 and fruit yield ha-1 were obtained from seedling treatments. Averaged over years, 50-69% increase in yield and 64-100% increase in profit were recorded in seedling treatments than direct seeded crop. Among seedling ages, 60 days old seedlings were the best performer. The overall results of two years study revealed that seedling transplantation was superior to traditional direct seeded practice of growing vegetable marrow and among those 60 days old seedlings was the best in respect of yield components, fruit yield and profit.SAARC J. Agri., 13(1): 215-222 (2015)
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Sykes, SR. "Effects of seedling age and size on chloride accumulation by juvenile citrus seedlings treated with sodium chloride under glasshouse conditions." Australian Journal of Experimental Agriculture 25, no. 4 (1985): 943. http://dx.doi.org/10.1071/ea9850943.
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Chloride accumulation by juvenile citrus seedlings treated with sodium chloride for 56 days, using either nutrient solution culture (50 mM NaCl) or pot culture (75 mM NaCl) techniques under glasshouse conditions, was investigated in relation to seedling age. Ranking of cultivars on the basis of leaf chloride concentrations varied according to the age of seedlings examined. Leaf chloride concentrations of 6-, 5-, 4- and 3-month-old seedlings of eight cultivars examined in solution culture decreased with seedling age and were negatively correlated with seedling dry weight within some cultivars. Cultivar differences in leaf chloride concentrations, which occurred for all age groups, were negatively correlated with shoot growth and seedling dry weight for 5-month-old seedlings only. Leaf chloride concentrations of seedlings treated with NaCl in pot culture also changed with the age of seedlings (5, 17- and 29-monthsold) and varied between cultivars, with significant cultivar x age interactions. The effect of seedling size on chloride accumulation was investigated using nutrient solution culture. Six-month-old seedlings of four varieties were treated with NaCl (50 mM) for 56 days. Two size classes were obtained by growing seedlings at two densities before salt treatment. Small seedlings had greater shoot chloride concentrations than equivalent large seedlings and cultivar ranking, based on shoot chloride concentrations, changed with seedling size. Cultivar differences in leaf chloride concentrations were negatively correlated with seedling growth and dry weight for small seedlings but not for large seedlings. Seedling size had no effect on root chloride concentrations. The results suggest that screening very small seedlings for chloride exclusion is not feasible since rankings based on leaf chloride concentrations did not agree with documented data for grafted trees. There appeared to be a critical or threshold seedling age or size at or above which rankings for shoot chloride accumulation by good chloride excluders were consistent with documented field data. The results are discussed in relation to screening citrus hybrids for chloride exclusion under glasshouse conditions.
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Ren, Yun, Jianfang Zhu, Nazim Hussain, et al. "Seedling age and quality upon transplanting affect seed yield of canola (Brassica napus L.)." Canadian Journal of Plant Science 94, no. 8 (2014): 1461–69. http://dx.doi.org/10.4141/cjps-2014-021.
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Ren, Y., Zhu, J., Hussain, N., Ma, S., Ye, G., Zhang, D. and Hua, S. 2014. Seedling age and quality upon transplanting affect seed yield of canola (Brassica napus L.). Can. J. Plant Sci. 94: 1461–1469. Seedling quality is an essential indicator for seed yield in canola, which is affected by many factors, including seedling age. Two field experiments were conducted to compare canola seedling quality and seed yield on 30-, 35-, 40-, 45-, 50-, 55-, and 60-d-old seedlings in 2011 and 2012. The relationship between seedling quality traits and seed yield of different seedling ages was also analyzed. Results revealed that the highest seed yield obtained from 40-d-old seedlings was attributed to more branches and siliques per plant. The negative effect of young seedlings (30-d-old) on seed yield was greater than that of old seedlings (60-d-old). The reduction rates in seed yield on the 30- and 60-d-old seedlings were 25.7 and 18.2%, respectively, compared with the 40-d-old seedlings. Increased root neck diameter, green leaf number, shoot, and root dry matter was the case on 40-d-old seedling transplanted plants compared with other ages. However, the increase was larger in the old seedlings than in the young seedlings. On average, the shoot and root dry weights of the 30-d-old seedlings were 1.9 and 1.7% of those in the 60-d-old seedlings. However, correlation analysis revealed that the seedlings with the highest shoot and root dry matter did not necessarily obtain the highest seed yield. Factor analysis suggested that the effects of root neck diameter and green leaf number on seed yield were more pronounced than those of shoot and root dry matter. Therefore, high seed yield in canola could be defined in terms of optimum green leaf numbers and branches per plant.
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Chaney, William R., and William R. Byrnes. "Effect of Seedling Age and Taproot Length on Performance of Oak." Northern Journal of Applied Forestry 10, no. 4 (1993): 175–78. http://dx.doi.org/10.1093/njaf/10.4.175.
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Abstract White oak and northern red oak seedlings were planted in an old field site in Indiana and evaluated for 9 yr to determine if seedling age and initial taproot length affected growth performance. Both 1-0 and 2-0 seedlings were produced in specially designed containerized seedbeds that provided for root pruning to lengths of 23 and 30 cm through control of the level of water saturation in the rooting medium. Survival of both species was high, 95%-100%. Northern red oak growth was not significantly influenced by initial seedling age or taproot length. White oak, however, performed the best when seedlings were 2 yr old and had a 30 cm long taproot. Seedling age was the more important factor affecting growth. North. J. Appl. For. 10(4):175-178.
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South, David B., and James L. Rakestraw. "A Loblolly Pine Seedling-Grade by Genotype Study." Southern Journal of Applied Forestry 26, no. 3 (2002): 153–58. http://dx.doi.org/10.1093/sjaf/26.3.153.
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Abstract A loblolly pine (Pinus taeda L.) seedling grade study was established in January 1987 on a Coastal Plain site at Bellville, Georgia. The factorial study involved three seedling grades (Wakeley's Grade 1, 2, and 3) and three half-sib families (#5, 25, 56). Trees were measured at ages 8 and 13 yr. Both family and seedling grade affected survival, height, and diameter at age 8 yr. Survival among families varied by as much as 3 percentage points while there was a 10 percentage point difference between Grade 1 and Grade 2 seedlings. Only family was related to height and diameter at age 13. Volume gains from planting Grade 1 seedlings instead of Grade 3 seedlings varied by family but there were no significant interactions between family and seedling grade. Differences in height among families and among seedling grades decreased over time. At age 8, there was a 5.3 ft difference between the tallest and shortest family but by age 13, the difference declined to 3.7 ft.Overall, planting family 56 instead of family 25 resulted in an additional 645 ft3/ac by age 13. Planting Grade 1 seedlings instead of Grade 3 seedlings produced an additional 303 ft3/ac. Per acre volume differences among families were greater at age 13 than at age 8. In contrast, differences among seedling grades were about the same at age 8 and 13 yr. The overall mean annual increment (MAI) for this study was 207 ft3/ac/yr. In comparison, the MAI for Grade 1 seedlings of family 56 was 239 ft3/ac/yr. South. J. Appl. For. 26(3):153–158.
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Fu, Wei, Jinqiu Gao, Chunjiang Zhao, Kai Jiang, Wengang Zheng, and Yanshan Tian. "Detection Method and Experimental Research of Leafy Vegetable Seedlings Transplanting Based on a Machine Vision." Agronomy 12, no. 11 (2022): 2899. http://dx.doi.org/10.3390/agronomy12112899.
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In view of the need to remove empty cells and unqualified seedlings for automatic transplanting of leafy vegetable seedlings, this paper proposes a method to detect the growth parameters of leafy vegetable seedlings by using machine vision technology. This method uses the image processor PV200 to perform image grayscale, threshold segmentation, corrosion, expansion, area division, etc. to obtain the pixel value of the leaf area of the seedling and compare it with the set standard value, which provides guiding information for eliminating empty cells and unqualified seedlings. Lettuce seedlings at 17 days, 20 days, and 22 days of seedling age were used as the test objects, and the growth status and test results of the seedlings were analyzed to determine the optimum seedling age for transplanting. The test results show that there is basically no leaf cross-border between the lettuce seedlings at the age of 17 days, the average pixel area of the leaves is 3771.74, and the detection accuracy rate is 100%; the seedlings at the age of 22 days grow 5–6 leaves, the detection accuracy of unqualified seedlings and qualified seedlings was 62.50% and 88.16%, respectively, and the comprehensive detection accuracy was 85.71%. The comprehensive detection accuracy rate showed a downward trend with the increase of seedling age, mainly due to the partial occlusion between leaves. The transplanting of leafy vegetable seedlings is a sparse transplanting operation, and the seedling spacing increases after transplanting. Therefore, the detection of seedlings in the process of transplanting can greatly improve the recognition accuracy and solve the problem that the leaves of the seedlings in the seedling tray are obscured by each other and affect the detection accuracy. The research results can provide a theoretical basis and design reference for the development of the visual inspection system and the transplanting actuator of the leafy vegetable seedlings transplanting robot.
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CLOUTIER, Y., L. PELLETIER, and R. MICHAUD. "DEVELOPMENT OF A TEST FOR FREEZING TOLERANCE IN YOUNG ALFALFA SEEDLINGS." Canadian Journal of Plant Science 70, no. 1 (1990): 307–10. http://dx.doi.org/10.4141/cjps90-036.
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An experiment was conducted to study the effects of seedling age on their ability to harden, and to determine whether cultivar × seedling age interaction could be identified for frost resistance. In the present study, 6- to 24-d-old alfalfa (Medicago sativa L.) seedlings were significantly more freezing-tolerant after cold-hardening than unhardened controls. Cold-hardened seedlings of age varying from 8 to 24 d were hardier than 6-d-old seedlings. No cultivar × seedling age interaction was found. The best separation of the cultivars occurred between 18 and 24 d. These findings provide additional information towards the development of a rapid and reliable test for estimating freezing tolerance in alfalfa.Key words: Freezing test, alfalfa, cold hardiness, seedlings
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Hosain, S. Akter S. Chakraborty N. Hossen S. Hossen K. and Rabbani M.D. "Effect of age of seedlings on the performance of drought tolerant Aman rice cultivars." Archives of Agriculture and Environmental Science 3, no. 4 (2018): 388–93. https://doi.org/10.26832/24566632.2018.0304010.
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An experiment was conducted at the Field Laboratory of the Department of Agriculture, Noakhali Science and Technology University (NSTU), Sonapur, Noakhali, from July 2017 to December 2017 to study the effect of variety and age of seedling on yield performance of drought tolerant transplant <em>aman </em>rice. The experiment consisted of three varieties viz. BINA dhan7, BRRI dhan56 and BRRI dhan71 and five different ages of seedling viz.15 days old, 20 days old, 25 days old, 30 days old, and 35 days old. The experimental design was randomized complete block design (RCBD) with three replications. Among the three varieties, BRRI dhan71 produced the highest grain yield (5.567 t ha<sup>-1</sup>) and the lowest grain yield (4.975 t ha<sup>-1</sup>) was obtained from BRRI dhan56. Among the five ages of seedlings, the highest grain yield (5.502 t ha<sup>-1</sup>) was obtained from 35 days old seedling and the lowest grain yield (5.092 t ha<sup>-1</sup>) was obtained from 15 days old seedling. In case of interaction between variety and spacing, the highest grain yield (5.723 t ha<sup>-1</sup>) was obtained from BRRI dhan71 with 35 days old seedling and the lowest (4.730 t ha<sup>-1</sup>) was obtained from BRRI dhan56 with 15 days old seedling. The result reveals that relatively older seedlings (35-days old) produce higher grain yield compared to the younger ones.
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TEEKAM SINGH, B.S. SATAPATHY, B. LAL, and K.B. PUN. "Productivity and profitability of rice (Oryza sativa) varieties as influenced by age of seedlings in north-eastern Himalayan region." Indian Journal of Agronomy 63, no. 3 (2024): 307–11. http://dx.doi.org/10.59797/ija.v63i3.5652.
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An experiment was conducted during boro (rabi) season of 2012–13 and 2013–14, at Gerua, Kamrup, Asom, India, to study the effect of different age of seedlings on growth and yield of rice (Oryza sativa L.) varieties. Ten treatment combinations of 2 different duration rice varieties, i.e. ‘Chandrama’ (175 days) and ‘Naveen’ (155 days), and 5 ages of seedlings (40, 50, 60, 70 and 80 days) were tested. ‘Chandrama’ rice recorded significantly higher grains/panicle and 1,000-seed weight as well as grain yield (5.93 and 6.50 t/ha) over ‘Naveen’ rice. Days to 50% flowering decreased with the increment in age of seedling by 2–10 days, whereas total maturity duration increased by 6–28 days. In case of age of seedlings, 40 and 50 days old seedlings showed higher values of growth and yield attributes that reflected in grain yield. There was gradual yield decrease with increment in the age of seedling due to reduced values of tillers/m2 , filled grains/panicle. The yield penalty was non-significant in case of long-duration rice variety ‘Chandrama’, while in case of ‘Naveen’, there was significant reduction in grain yield when seedling age exceeded beyond 60 days. ‘Naveen’ rice with 40 and 50 days old seedlings recorded significantly higher grain yield over 70 and 80 days seedlings respectively. Earlier farmers using their own local rice landraces which were long duration and less affected by age of seedling but with development of new semi-dwarf, medium-duration rice varieties need to be transplanted at optimum age of seedling. Thus, the age of seedling can be extended up to 60 days for those rice varieties having long duration (>175 days) while for short duration (<155 days), it should not be extended beyond 50 days.
Dissertations / Theses on the topic "Seedling age"
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Barton, Kasey Elisabeth. "Seedling defense strategies: Effects of plant age, herbivory and competition." Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3256440.
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Dugo, Tesfaye Letta <1976>. "Association mapping of stem rust resistance in durum wheat at the seedling and adult plant stages." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5935/1/Dugo_Tesfaye_tesi.pdf.
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In wheat, stem rust is known to rapidly evolve new virulence to resistance genes. While more than 50 stem rust resistance (Sr) loci have been identified in wheat, only a few remain effective, particularly against the highly virulent race Ug99 (TTKSK race) and a mixture of durum-specific races. An association mapping (AM) study based on 183 durum wheat accessions was utilized to identify resistance loci for stem rust response in Ethiopia over four seasons and artificial inoculation with Ug99 (TTKSK race) and a mixture of durum-specific races under field conditions as well as in greenhouse test at seedling stage under controlled conditions for resistance to four highly virulent stem rust races: TRTTF, TTTTF, (TTKSK (Ug99) and JRCQC. The panel was profiled with 1,253 SSR and DArT markers. Twelve QTL-tagging markers were significant (P < 0.05) across three to four seasons. The role of Sr13, Sr9, Sr14, Sr17, and Sr28 was confirmed. Thirteen significant markers were in regions with no Sr genes/QTLs.
The results under controlled conditions showed that 15, 20, 19 and 19 chromosome regions harbored markers that showed significant effects for races TRTTF, TTTTF, TTKSK and JRCQC, respectively. These genomic regions showed marker R2 values ranging from 1.13 to 8.34, 1.92 to 17.64, 1.75 to 23.12 and 1.51 to 15.33% for races TRTTF, TTTTF, TTKSK and JRCQC, respectively. The study demonstrates that stem rust resistance in durum wheat is governed in part by shared loci and in part by race-specific ones. The QTLs identified in this study through AM will be useful in the marker-assisted development of durum wheat cultivars with durable stem rust resistance.
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Dugo, Tesfaye Letta <1976>. "Association mapping of stem rust resistance in durum wheat at the seedling and adult plant stages." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5935/.
Full textAbstract:
In wheat, stem rust is known to rapidly evolve new virulence to resistance genes. While more than 50 stem rust resistance (Sr) loci have been identified in wheat, only a few remain effective, particularly against the highly virulent race Ug99 (TTKSK race) and a mixture of durum-specific races. An association mapping (AM) study based on 183 durum wheat accessions was utilized to identify resistance loci for stem rust response in Ethiopia over four seasons and artificial inoculation with Ug99 (TTKSK race) and a mixture of durum-specific races under field conditions as well as in greenhouse test at seedling stage under controlled conditions for resistance to four highly virulent stem rust races: TRTTF, TTTTF, (TTKSK (Ug99) and JRCQC. The panel was profiled with 1,253 SSR and DArT markers. Twelve QTL-tagging markers were significant (P < 0.05) across three to four seasons. The role of Sr13, Sr9, Sr14, Sr17, and Sr28 was confirmed. Thirteen significant markers were in regions with no Sr genes/QTLs.
The results under controlled conditions showed that 15, 20, 19 and 19 chromosome regions harbored markers that showed significant effects for races TRTTF, TTTTF, TTKSK and JRCQC, respectively. These genomic regions showed marker R2 values ranging from 1.13 to 8.34, 1.92 to 17.64, 1.75 to 23.12 and 1.51 to 15.33% for races TRTTF, TTTTF, TTKSK and JRCQC, respectively. The study demonstrates that stem rust resistance in durum wheat is governed in part by shared loci and in part by race-specific ones. The QTLs identified in this study through AM will be useful in the marker-assisted development of durum wheat cultivars with durable stem rust resistance.
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Sekharan, Soja. "Aged soybean (Glycine max [L.] Merrill) seeds – their physiology and vigor assessment." The Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=osu1135809134.
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Persico, M. "A FORWARD GENETICS APPROACH TO STUDY SEED AND SEEDLING DEVELOPMENT IN MAIZE." Doctoral thesis, Università degli Studi di Milano, 2015. http://hdl.handle.net/2434/336051.
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Embryogenesis, germination and early phases of seedling growth represent critical phases in the plant life cycle and are probably the most important events in determining the success of an annual plant.
A rapid and robust emergence positively influences the capacity of the plant to take advantage of the favourite environment and to compete with its neighbours. In the perspective of a more sustainable agriculture specific characters are envisaged for a crop seedling, such as the resistance to environmental critical abiotic as well as biotic factors. For these reasons key factors subtending plant developmental process and contributing to the achievement of a productive and robust plant have to be searched inside the genetic network that control embryo and seedling development.
Among the different aspects affecting seedling development the two that will be analysed in this study play an important role also in the interplay with the environment. Hormones are endogenous signals governing seedling growth and architecture establishment but at the same time are able to induce plant response to environmental stress. Wax deposition is required for determining a correct embryo and seedling development, and provides, beside that, a protective barrier that plants produce in their early developmental phases to defend themselves from pathogens as well as from variation in environmental abiotic components, such as temperature and water availability.
Here, we report the characterization of the mutants lilliputian 1-1 (lil1-1) and fused leaves 1-1 (fdl1-1), both ascribable to defective seedling (des) maize mutants.
lilliputian 1-1 (lil1-1) is a monogenic recessive mutant of maize, isolated from an active Mutator (Mu) stock and attributed to the insertion of a Mutator1 element in the first exon of a the gene encoding the BR C-6 oxidase. The enzyme belongs to the superfamily of CYP85A proteins and catalyzes the final steps of brassinosteroid synthesis. lil1-1 mutant exhibits a reproducible phenotype consisting of a large primary root, extremely reduced stature and crinkly leaves. Recently, another dwarf mutant of maize impaired in the same brassinosteroid C-6 oxidase and showing a very similar phenotype of lil1-1 has been characterized and the corresponding gene was termed brasssinosteroid deficient 1 (brd1)
Allelism between the two mutant alleles has been demonstrated in this work. Moreover, it has been observed that the exogenous application of brassinolide to the lil1 mutant seedlings resulted in a partial recovery of the lil1-1 phenotype. This observation is in agreement to what previously observed for brd1-m in maize and other Br-deficient mutants in Arabidopsis, rice and tomato.
Differently from some of these mutants, i.e det2 of Arabidopsis, lil1 genotype does not influence the seed formation and development. It is evident that the comparison between homozygous lil1-1 mutant and Li11-1 wild-type seeds from the same segregating ear did not highlight any difference in weight. In addition, F2 progeny ears obtained from F1 heterozygous Lil11/lil1-1 or homozygous Lil1-1/Lil1-1 plants showed the same average kernel number and total kernel weight per ear and the average weight of single kernel.
BRs are also involved in the modulation of stress responses. Water loss assays and measurement of gas exchange demonstrated that lil1-1 plants lost less water and maintained efficient gas exchange under drought stress for longer time than wild-type siblings.
Our hypothesis is that lil1-1 mutant is more tolerant to drought stress because it is by default in a physiological water stress condition. A similar interpretation has been proposed to explain the behaviour of the det2 mutant in Arabidopsis that is deficient in a steroid reductase. The det2 mutant showed an enhanced resistance to general oxidative stress, correlated with a constitutive increase in superoxide dismutase (SOD) activity and increased transcript levels of the defence gene catalase (CAT).
To confirm this hypothesis, other studies must be performed, among them the expression analysis of genes involved in dehydration stress. However, the hypothesis is at the moment supported by the observation that lil1-1 mutant plants show phenotypic traits that are generally present in plant subjected to water stress, i.e. inhibition of lateral root growth, reduction in leaf area and plant growth, enlarged leaf thickness and increased stomatal density.
The fdl1-1 mutant, previously isolated in our laboratory, allowed the identification and functional analysis of a novel maize MYB gene. The fdl1-1 mutation was caused by an Enhancer/Suppressor (En/Spm) element insertion in the third exon of the sequence encoding ZmMYB94, a transcription factor of the R2R3-MYB subfamily.
In this work, proof of gene identity was obtained using an RNAi approach and by the analysis of the mutant cDNA sequence. The first experiment ascertained the lesion in the third exon of the sequence encoding ZmMYB94. The second approach confirmed that the mutant transcript retains the En/Spm element.
The fdl1-1 mutant phenotype is expressed at early stages of seedling development, from germination to the three-four leaves stage, causing a general delay in germination and seedling growth as well as phenotypic abnormalities. The main features of mutant plants are irregular coleoptile opening and the presence of regions of adhesion between the coleoptile and the first leaf and between the first and second leaves. A previous study showed that fusions could be attributable to the alterations in cuticle deposition and highlighted an irregular wax distribution on the mutant leaf surfaces. Phylogenetic analysis demonstrated that its closest Arabidopsis related genes, i.e. MYB30, MYB94 and MYB96 have all been implicated in the regulation of cuticular wax biosynthesis in Arabidopsis.
To gain insight into the role exerted by ZmMYB94 a deeper characterization of cuticle components were therefore undertaken in this study by comparing mutant and wild-type tissues. We found a significant reduction of the amount of waxes in the mutant versus wild-type samples at earlier developmental stages. In particular, the production of C32 alcohols, which is the major compound of cuticular waxes in the maize seedling, resulted drastically reduced in the mutants and replaced by shorter chain alcohol (C26, C28 and C30) and alkane (C29).
On this basis, we speculate that ZmMYB94 specifically affects the activity of enzymes involved in the elongation of long chain wax molecules at the C30—C32 step.
In maize, some glossy mutants, i.e glossy 2 and glossy 4 show the same block in the long chain elongation. Thus, some of the subtending genes could be under the control of ZmMYB94. Contrary to fdl1-1, none of glossy mutant of maize so far characterized showed post-genital organ fusion. This difference could be due to a greater decrease (more than 90%) of epicuticular waxes observed in the fdl1-1 mutant than in glossy mutants. It is also conceivable that ZmMYB94 affects directly or indirectly the expression of a set of genes involved in the biosynthesis of very-long-fatty acids and the failure of multiple activities has caused a worsening of the phenotype. Alternatively, ZmMYB94 could regulate also some genes involved in the biosynthesis of other cutin components. Although only minor changes in the cutin load were observed in the fdl1-1 mutant, the affected components could be important for determining organ separation.
Recent studies strongly support the idea that cuticular wax accumulation contributes to drought resistance. However, it is still not known in crops how wax related genes are regulated in response to drought. In our study, an increment of water loss in the mutant seedlings has been demonstrated and a correlation between the severity of the phenotype and the rate of water loss was revealed. Moreover, we found that the transcript level of ZmMYB94 increased in plant under drought stress condition. Similarly to AtMYB30, AtMYB94 and AtMYB96, which are considered positive regulators of wax biosynthesis during stress, it is conceivable that ZmMYB94 stimulates the activity of genes involved in cuticular waxes biosynthesis thus contributing to increase drought tolerance in the early phases of maize seedling growth.
In conclusion, our study further indicate that the study of BR-related mutants and mutants impaired in cuticular waxes biosynthesis could be important for unravelling the molecular mechanisms underlying stress response in early developmental phases of cultivated plants and ultimately to identify new genetic tools of interest for their application in designing new breeding strategies.
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ZILIO, MASSIMO. "FUNCTIONAL ANALYSIS OF MAIZE GENES INVOLVED IN SEEDLING DEVELOPMENT AND IN PLANT ¿ ENVIRONMENT INTERACTION." Doctoral thesis, Università degli Studi di Milano, 2018. http://hdl.handle.net/2434/545423.
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Maize is one of the most important cultivated plants on a world scale, with a total production which exceeds one billion tonnes per year (FAOSTAT 2017). It is an important human food source in many parts of the world, but is also intensely exploited for biofuel and feed production. Furthermore, maize is also a model plant for research studies in the field of biology and genetics. For these reasons, maize is one of the most intensively studied crops, with the aim of improving its productivity, which in the USA has increased nearly five times since the 1940s. This dramatic yield improvement is due to the development and widespread use of new farming technologies. An important role was played by genetic improvement, with the use of highly productive maize hybrids and, more recently, biotechnology.
However, the increases in annual productivity of maize and the other main crops exploited for food production seem to have reached a stall phase in recent years.
It has been estimated that the world population will increase from 7.5 to 9.7 billion people by 2050. To meet the food needs of the increasing population, and to satisfy diets that will include more meat, according to the Food and Agricultural Organization (FAO), worldwide crop production will have to increase by 70%. It is a tough task, made even more difficult by the fact that the worldwide area of cultivable soil is decreasing as a consequence of increasing urbanization and climate change.
To reach the target, new strategies are required, which will include multiple and integrated approaches, among them genetic improvement. One of the main challenges will be to develop new plant ideotypes that will combine the capability to tolerate biotic and abiotic stress with no reduction in yield.
Within this perspective, the work carried out in this thesis project was aimed at understanding the molecular mechanisms involved in plant response to environmental factors.
The work was organized in two parts, which are presented here in two different chapters. Both chapters are focused on genes that control plant development as well as plant- environment interactions.
The first chapter deals with the study of the genetic regulation of cuticle deposition in maize. The cuticle is an important plant organ and constitutes the first barrier against many environmental stresses, including water deprivation and pathogen interaction. The cuticle is produced by epidermal cells and is composed of a complex array of long chain hydrocarbons, constantly deposed on the aerial surface for all the plant’s life.
To investigate the cuticle biosynthesis process in maize, our strategy was based on the functional characterization of ZmMYB94, also known as fused leaves 1 (fdl1). This gene encodes a transcription factor of the R2R3-MYB subfamily, expressed in embryo, seedling and silk tissues. A mutant in this gene, referred to as fdl1-1, was available for this study. It originated from the insertion of an Enhancer/Suppressor (En/Spm) element in the third exon of the ZmMYB94 gene. The mutation has a pleiotropic effect on seedling development. The main features of fdl1-1 mutant plants are irregular coleoptile opening and the presence of regions of adhesion between the coleoptile and the first leaf and between the first and second leaves.
Deeper studies of the fdl1-1 mutant, performed by electron microscopy analysis, showed that, in regions of organ adhesion, cuticle was absent and, on the epidermal surface, epicuticular wax deposition occurred irregularly. These observations led to the hypothesis that phenotypic alterations observed in the mutant seedlings may be attributable to defects in the cuticle-related biosynthetic pathways.
To gain insight into the role of fdl1 in controlling cuticle formation, a large-scale RNA sequencing analysis was carried out in this work. By means of this approach, more than one thousand differentially expressed genes (DEGs) were found in the fdl1-1 mutant compared with the wild type seedling transcriptome.
The analysis of single DEGs confirmed that fdl1 is involved in the regulation of the biosynthesis of both cuticle components, since genes for the cuticular waxes deposition as well as cutin biosynthesis were detected.
In particular, five genes with a reduced expression level and one with an increased expression level in the fdl1-1 mutant encoded for enzymes involved in the Fatty acid elongation complex, the main source of basic compounds exploited in cutin and waxes biosynthesis. Furthermore, two genes found with a reduced expression level in the mutant were also involved in the cutin biosynthesis. Interesting sidelights on these two genes are available from the study of their orthologues in rice (OsONI3) and in Arabidopsis (AtEDA17). The knock-out mutant of ONI3 in rice shows a phenotype that is very similar to that of the fdl1-1 mutant in maize, with defects in cutin deposition and fusions between the coleoptile and the first leaves. Moreover, the knock-out mutant of EDA17 in Arabidopsis shows defects in cutin deposition and fusions between floral organs.
Other two genes found differentially expressed in fdl1-1 encode for enzymes involved in epicuticular waxes biosynthesis, thus explaining the defects observed in fdl1-1 mutants.
On the basis of these observations, we developed a model that explains the mode of action of fdl1 in controlling cuticle formation.
Furthermore, the large-scale RNA sequencing analysis done in this study revealed a considerable number of genes differentially expressed in the fdl1-1 mutant that are involved in other important processes, such as plant clock regulation, plant pathogen interaction and hormone signalling. A deeper investigation of the role of these genes will be of help in elucidating the action of fdl1 in controlling different aspects of plant development.
We also demonstrated in the present study that fdl1 is actively involved in the drought stress response in maize seedlings. Indeed, an expression analysis showed strong differences in the fdl1 transcript level in seedlings exposed to drought stress condition compared with seedlings grown in well-watered conditions. Indeed, in normally watered plants, the fdl1 transcript level constantly increased during leaf expansion, until it reached a high expression level. In plants exposed to drought stress conditions, the fdl1 transcript level showed a different pattern, with a strong increment in the first day of stress, and then a decrease until the initial level was reached and maintained for the whole duration of drought conditions.
We may speculate that the involvement of fdl1 in the plant response to drought conditions, consists in promoting a modification of cuticle composition that will reduce water loss.
To further investigate the involvement of fdl1 in drought stress tolerance, its orthologous gene was identified in Eragrostis curvula. This species is particularly interesting for our purposes, because its genome is very similar to the maize genome. Furthermore, unlike maize, in Eragrostis different ecotypes, characterized by different drought stress tolerance, have been described.
In a preliminary analysis, we observed that the expression pattern of Ecfdl1 is different among three Eragrostis ecotypes. Differently from what was observed in maize, Ecfdl1 appeared to be expressed in different adult tissues. Moreover, differences in the Ecfdl1 expression profile were detected in different ecotypes.
Besides in young maize tissues, fdl1 also appears to have an active role in controlling cuticle deposition in silk tissues. We detected differences between the fdl1-1 mutant and wild type plants in the composition of the wax layer covering the silks.
Since maize silks constitute the main route of entry for pathogens to reach the seeds, in our opinion the differences found in silk coverage can influence the plant-pathogen interaction.
This hypothesis was confirmed by comparing fusarium ear rot symptoms between wild type and fdl1-1 mutant ears experimentally inoculated with Fusarium verticillioides in a two year experiment. Our results seem to indicate that the fdl1-1 mutant is less susceptible to fusarium infection compared with the wild type.
In conclusion to this part of the work, our studies provided details about the involvement of fdl1 in the regulation of cuticle biosynthesis and deposition during two of the most important moments of the plant life cycle: the seedling stage and silk development. Furthermore, in these two delicate moments, we have evidence showing that fdl1 plays an active role in drought stress response and pathogen interaction.
In the second chapter, the role of brassinosteroids (BRs) in leaf permeability and architecture was further analysed. BRs are a class of steroid hormones essential for plant growth and development. BRs are involved in many developmental traits of agronomic importance such as seed germination, plant architecture, flowering time and seed yield. In addition to having an important role in development, brassinosteroids exert anti-stress effects on plants and are essential for the ability of plants to adapt to abiotic stresses.
This part of the work was focused on the characterization of the maize lilliputian1-1 (lil1-1) mutant, which is impaired in one of the last steps of brassinosteroid biosynthesis. The subtending gene putatively encodes for a brassinosteroid C-6 oxidase (brC-6 oxidase). The mutant appears severely compromised in height, floral development and overall plant architecture. Leaf primordia are more compressed compared with wild type, and mutant leaves appear thicker than wild type leaves, exhibiting altered shape and the presence of supernumerary cell layers in the mesophyll region between the leaf vessels and the adaxial leaf epidermis.
In this study, alterations in epicuticular waxes deposition were found in the lil1-1 mutant. Furthermore, it was shown that the leaf epidermis of lil1-1 shows a significantly lower permeability than wild type. These findings are in accordance with previous observations obtained in our laboratory, which showed that the lil1-1 mutant shows a better dehydration tolerance.
In our hypothesis, the thicker epidermis observed in lil1-1 compared with wild type, can explain the lower permeability and the better dehydration tolerance.
Furthermore, in this chapter we used the lil1-1 mutant to better investigate the BRs biosynthesis pathway. This is a complex pathway and, although it has been the subject of several studies in recent years, some aspects are still to be clarified.
For this purpose, we analysed the interaction between the lil1-1 mutant, and another well-known maize BRs mutant, i.e. the nana1-1 (na1-1) mutant. Both nana1 and lil1 genes have key roles in the BR biosynthesis pathway. The product of nana1 is involved in two parallel pathways, therefore lack of its action may lead to an interruption of both. The lil1 gene product, however, is involved in the last steps of the pathway, leading to the formation of castasterone and brassinolide.
Our analysis revealed that lil1-1 is epistatic to na1-1. These data suggest the existence in the maize BR pathway of an additional na1-independent branch leading to the production of CS precursors.
In conclusion, this part of the work demonstrated the involvement of brassinosteroids in passive leaf permeability and provided new information that will be useful to unravel the complex BR biosynthetic pathway in plants.
Overall, the work developed in this thesis project provides indications useful to better understanding the genetic mechanisms that regulate plant resistance to drought and pathogens.
A good comprehension of these mechanisms can ultimately be useful to identify new genetic tools of interest, and to develop crops more adapted to the challenges of the future.
Because of the appointment with 2050, only 32 annual production cycles remain.
7
Giolo, Maurizio. "Germination, seedling growth and establishment of warm-season turfgrasses related to climate changes in the Mediterranean region." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3422696.
Full textAbstract:
The Mediterranean region is located from the arid climate of North Africa up to the temperate and rainy climate of northern and central Europe. Climate simulations show a gradual increase in heating, drying and precipitation variability in this region. These effects will probably push warmseason turf species towards minor latitudes. The consequences of climate change on turfgrass management have been investigated only recently. Germination and seedling growth have also been little studied for the response to climate change effects, although the establishment phase is central to any high-performing turfgrass. For warmseason grasses in the transition zone, a quick establishment increases winter survival and allows for earlier spring green-up and a more rapid recovery from winter injury. In the Mediterranean region, warm-season grasses are commonly seeded in late spring when the
temperatures are suitable for a rapid establishment. Warm-season species used extensively by the turf industry have fertile and sterile cultivars. Seeded cultivars are usually preferred over sterile cultivars because seeding is cheaper and easier to practice than vegetative propagation methods which include plugging, sprigging, and stolonizing. The present study concerns two of the most used warm-season turf species in the Mediterranean
area: Bermudagrass (Cynodon spp.) and seashore paspalum (Paspalum vaginatum Swartz) and one potential future new species i.e.buffalograss [Buchloe dactyloides (Nutt.) Engelm.]. The research activity scheduled consisted of five experiments conducted in the field and controlled environments (growth chamber and greenhouse) to investigate the effects of suboptimal temperatures and excess of water due to flooding on seed germination and seedling growth. The main results were the following: Effects of sub-optimal temperatures The warm-season grasses tested germinated at a temperature equal or higher than 11.4 °C (base germination temperature) and early April is the optimal seeding time for establishing by seed warmseason turfgrasses in the Po-Venetian valley. From these results, we have concluded that the predicted warmer springs should lead to earlier seeding of warm-season grasses favouring turfgrass maturation before winter. Effects of water excess All three warm-season turf species under study tolerate flash waterlogging. However, bermudagrass is the one less affected by prolonged waterlogging (6-8 days). In general, warm-season grasses can be successfully used for establishing turfgrasses considering the future climate change predicting the increase of extreme precipitation events.<br>La regione mediterranea è ubicata fra il clima arido del Nord Africa ed il clima temperato e piovoso dell'Europa settentrionale e centrale. Le previsioni sui cambiamenti climatici nei prossimi anni presentano un graduale aumento delle temperature e delle condizioni di aridità, come pure l’aumento di eventi piovosi intensi e localizzati. Per effetto di questi cambiamenti climatici si prevede un crescente impiego di specie macroterme (C4) a latitudini minori comprese quelle utilizzate per la formazione di tappeti erbosi. Le conseguenze sulla gestione del tappeto erboso sono state studiate solo di recente ed inoltre mancano risultati scientifici riguardo gli effetti prodotti dai cambiamenti climatici sulla germinazione e sulle prime fasi di crescita delle plantule. Nella regione mediterranea, le poacee macroterme vengono seminate in tarda primavera, quando le temperature consentono una pronta germinazione ed un rapido insediamento del tappeto erboso. Queste specie presentano sovente cultivar fertili e cultivar sterili che possono essere insediate unicamente per via vegetativa (plugging e stolonizzazione). Le cultivar da seme sono generalmente preferite alle cultivar sterili essendo la semina più economica e più facile da praticare di un insediamento per via vegetativa. Le fasi di insediamento del tappeto erboso seminato sono particolarmente importanti nella gestione dei tappeti erbosi in zone di transizione. Un rapido insediamento, infatti, consente alle specie macroterme di affrontare in condizioni ottimali i rigori invernali e riprendere rapidamente a vegetare in primavera. Il presente studio ha preso in esame due delle specie macroterme da tappeto erboso più utilizzate nell’area mediterranea: gramigna (Cynodon spp.) e paspalum vaginatum (Paspalum vaginatum Swartz) e una specie che potrebbe trovare possibilità di impiego nei prossimi anni e cioè buffalograss [Buchloe dactyloides (Nutt.) Engelm.]. L’attività di ricerca nell’ambito del dottorato prevedeva cinque esperimenti condotti in campo e in ambiente controllato (camera di crescita, serra), finalizzati allo studio degli effetti delle temperature sub-ottimali e dell’eccesso idrico, dovuto ad eventi piovosi intensi, sulla germinazione dei semi e sulla crescita delle plantule delle suddette specie macroterme. I risultati più significativi sono di seguiti riportati. Effetti di temperature non ottimali È stato dimostrato che la germinazione delle specie macroterme testate avviene solamente quando la temperatura è uguale o superiore a 11,4 °C e che l’inizio di aprile può essere considerato il momento ottimale per la semina di tali specie nella pianura padano-veneta. L’incremento termico previsto nei prossimi anni dovrebbe consolidare tali risultati. Una semina ad inizio aprile, diversamente da quanto solitamente avviene (metà-maggio) consente di completare l’insediamento entro maggio, così il tappeto erboso avrà a disposizione l’intera estate per maturare e affrontare nel migliore dei modi l’inverno. Effetti dell'eccesso idrico. Le nostre ricerche hanno evidenziato la spiccata attitudine delle tre specie oggetto di studio a sopportare il ristagno idrico. In particolare, la gramigna è risultata la specie più tollerante all’eccesso idrico nel suolo durante l’insediamento, conservando la germinabilità ed una buona crescita delle plantule anche dopo 6-8 giorni di sommersione. In generale, possiamo affermare che le specie macroterme da tappeto erboso possono essere di grande interesse per la realizzazione di tappeti erbosi nelle condizioni prospettate dai futuri scenari legati al cambiamento climatico.
8
SANTOS, Renata Soares dos. "Fungos micorr?zicos arbusculares na produ??o de mudas de Albizia polycephala." Universidade Federal Rural do Rio de Janeiro, 2016. https://tede.ufrrj.br/jspui/handle/jspui/1608.
Full textAbstract:
CAPES<br>Currently there is a need to produce seedlings at low cost and with high quality to be used in the recovery of degraded areas and the use of arbuscular mycorrhizal fungi (AMF) can improve their development in low fertility soils. AMF have several benefits for the plants, because they promote increased survival and establishment of seedlings in the field, as with the symbiosis hyphae improve water use and nutrients. And before this, the present study aimed to evaluate the growth of seedlings Albizia polycephala inoculated with different AMF. First they were produced inoculants through traps vessels with species of native AMF obtained from samplings in the rhizosphere of matrices Albizia polycephala. Later two experiments were conducted, the first being tested five species of AMF from the Collection arbuscular mycorrhizal fungi of Embrapa Agrobiology (COFMEA), mounted in a completely randomized block design with six treatments (control - without inoculation, Scutellospora calospora (T.H. Nicolson & Gerd.) C. Walker & F.E. Sanders, Acaulospora colombiana (Spain & N.C. Schenck) Kaonongbua, J.B. Morton & Bever, Claroideoglomus etunicatum (W.N. Becker & Gerd.) C. Walker & A. Sch??ler, Dentiscutata heterogama (T.H. Nicolson & Gerd.) Sieverd., F.A. Souza & Oehl e Gigaspora margarita W.N. Becker & I.R. Hall) and nine repetitions. In the second experiment inoculants native AMF were tested (native inoculant) and the best species of AMF in the first experiment (Embrapa inoculant). The experimental design was randomized blocks with eight repetitions, in a factorial 3 x 4, that is, three treatments (a witness - no inoculation and two inoculants - native inoculum and mixture of three species from COFMEA) and four doses of P (0, 35, 140 and 350 mg/dm?), applied in the form of superphosphate. The seed Albizia polycephala germinated in trays with sand and vermiculite (2: 1with based on volume) and when the seedlings had a pair of leaves were transplanted with the inoculant in plastic containers of 700 ml with PVC cartridge 380 cm? coupled your background. During the experiments were conducted biweekly measurements of height and diameter and after collection, the root colonization rate assessments, spore density, dry matter of shoot, root dry matter, reason root /shoot and leaf phosphorus content . The results obtained through the evaluations showed that the species of Acaulospora colombiana was the most effective in promoting the growth of Albizia polycephala. Furthermore, the inoculant of COFMEA provided better growth in different phosphorus levels than native inoculant. Thus, it can be stated that the tested species has association with AMF efficiently and has high dependence mycorrhizal.<br>Atualmente existe a necessidade de se produzir mudas a baixo custo e com ?tima qualidade para serem utilizadas na recupera??o de ?reas degradadas e a utiliza??o dos fungos micorr?zicos arbusculares (FMAs) pode melhorar o seu desenvolvimento em solos de baixa fertilidade. Os FMAs apresentam v?rios benef?cios para as plantas, pois promovem uma maior sobreviv?ncia e estabelecimento das mudas no campo, j? que com a simbiose as hifas melhoram o aproveitamento de ?gua e nutrientes. E diante disso o presente trabalho teve como objetivo geral avaliar o crescimento de mudas de Albizia polycephala inoculadas com diferentes FMAs. Primeiramente foram produzidos inoculantes atrav?s de vasos armadilhas com esp?cies de FMAs nativos, obtidos a partir de coletas de solo na rizosfera de matrizes de Albizia polycephala. Posteriormente foram realizados dois experimentos, sendo no primeiro testadas cinco esp?cies de FMAs provenientes da Cole??o de fungos micorr?zicos arbusculares da Embrapa Agrobiologia (COFMEA), em blocos inteiramente casualizados, com seis tratamentos (Testemunha ? sem inocula??o, Scutellospora calospora (T.H. Nicolson & Gerd.) C. Walker & F.E. Sanders, Acaulospora colombiana (Spain & N.C. Schenck) Kaonongbua, J.B. Morton & Bever, Claroideoglomus etunicatum (W.N. Becker & Gerd.) C. Walker & A. Sch??ler, Dentiscutata heterogama (T.H. Nicolson & Gerd.) Sieverd., F.A. Souza & Oehl e Gigaspora margarita W.N. Becker & I.R. Hall) e nove repeti??es. No segundo experimento foram testados os inoculantes de FMAs nativos (inoculante nativo) e as melhores esp?cies de FMAs do primeiro experimento (inoculante Embrapa). O delineamento experimental utilizado foi em blocos casualizados com oito repeti??es, em fatorial 3 x 4, ou seja, tr?s tratamentos (uma testemunha ? sem inocula??o e dois inoculantes ? in?culo nativo e mistura de tr?s esp?cies provenientes da COFMEA) e quatro doses de P (0, 35, 140 e 350 mg/dm?), aplicado na forma de superfosfato simples. As sementes de Albizia polycephala germinaram em bandejas contendo areia e vermiculita (2:1com base em volume) e quando as pl?ntulas tinham um par de folhas foram transplantadas junto com o inoculante em recipientes pl?sticos de 700 ml com tubete de PVC de 380 cm? acoplado em seu fundo. Durante os experimentos foram realizadas medi??es quinzenais de altura e di?metro e ap?s a coleta, as avalia??es de taxa de coloniza??o da raiz, densidade de esporos, mat?ria seca da parte a?rea, mat?ria seca da raiz, raz?o raiz/parte a?rea e teor de f?sforo foliar. Os resultados obtidos atrav?s das avalia??es mostraram que a esp?cie de Acaulospora colombiana foi a mais eficiente em promover o crescimento de Albizia polycephala. Al?m disso, o inoculante da COFMEA proporcionou melhores crescimentos em diferentes doses de f?sforo do que o inoculante nativo. Desta forma, pode-se afirmar que a esp?cie testada apresenta associa??o com FMAs de forma eficiente e tem alta depend?ncia micorr?zica.
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Lima, Filho Pedro. "Bioss?lido na restaura??o florestal: forma??o de mudas e aduba??o de plantio." Universidade Federal Rural do Rio de Janeiro, 2015. https://tede.ufrrj.br/jspui/handle/jspui/1357.
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Previous issue date: 2015-05-22<br>Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES<br>One of the main problems found in forestry stands intended for restoration is seedling quality. The goal of this research was to evaluate different tube volumes in seedling production, utilizing biosolid as the substrate, within the following species; Ceiba speciosa, Pseudobombax grandiflorum, Dalbergia nigra and Lafoensia glyptocarpa,. The experiment consisted of the seedling production stage and a development evaluation stage in the field. The treatments utilized were 55, 110, 180 and 280 cm? tubes. The seedling production phase was done under entirely randomized design composed of four replications of the 12 seedlings. The field phase was also done under entirely randomized design due to the seedling formation period, which was in different periods for each species. The 280 cm? tube provided the best seedling quality, regardless of the species, when the biosolid was utilized as substrate. Despite this, for the species Pseudobombax grandiflorum, Dalbergia nigra and Lafoensia glyptocarpa, it is possible to utilize the 180 cm? tubet for seedling formation while maintaining similar quality<br>Um dos principais problemas encontrados na forma??o de povoamentos visando ? restaura??o florestal ? a qualidade das mudas. O objetivo deste trabalho foi avaliar diferentes volumes de tubetes para a produ??o de mudas de Ceiba speciosa, Pseudobombax grandiflorum, Dalbergia nigra e Lafoensia glyptocarpa, utilizando o bioss?lido como substrato. O experimento constou da fase de produ??o das mudas e da avalia??o do desempenho dessas no campo. Os tratamentos utilizados foram os tubetes de 55, 110, 180 e 280 cm?. A fase de produ??o das mudas foi instalada em delineamento inteiramente casulalizado composto por quatro repeti??es de 12 mudas. A fase de campo tamb?m foi instalada em delineamento inteiramente causualizado. Devido ao tempo de forma??o das mudas, em ?pocas diferentes para cada esp?cie. O tubete de 280 cm? foi o que proporcionou a melhor de qualidade de mudas, independente da esp?cie, quando se utilizou o bioss?lido como substrato. Todavia, para as esp?cies Pseudobombax grandiflorum, Dalbergia nigra e Lafoensia glyptocarpa pode-se utilizar o tubete de 180 cm? para a forma??o das mudas, mantendo qualidade similar
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Silva, Aldir Carlos. "Avalia??o da toler?ncia ao alum?nio em pl?ntulas de maracujazeiro e mamoeiro." Universidade Federal Rural do Rio de Janeiro, 2009. https://tede.ufrrj.br/jspui/handle/jspui/2402.
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Previous issue date: 2009-03-06<br>Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq<br>Aluminum tolerance studies in seedlings of Passion fruit (cvs. IAC-273/277, IACPaulista,
IAC-275, FB-100) and Carica papaya (cvs.Taiung, Golden, Gran Golden,
Baixinho de Santa Amalia) were performed in a growth chamber at the Laboratories of
Chemistry of the Rhizosphere and Seeds of the Department of Fitotecnia, of University
Federal Rural of Rio Janeiro, Institute of Agronomy. Experiments with different
concentrations of Al were conducted in nutrient solution simple (with Ca) and complete,
with the aims to analyze the tap root length, ratio of root lengths, relative root
elongation, diameter of root and stem and effect of stains. Also were conducted
experiments with seeds soaked in different concentration of Al to verify the percentage
of germination, seedlings normal and abnormal. The use of simple nutrient solution was
not satisfactory to shown the performance of seedlings of papaya. In passion fruit both
nutrient solutions can be used in short term experiment. Over the concentration of
160?M of Al occurred effect of toxicity in root of seedlings of passion fruit and papaya,
but at concentrations lower that 80?M there were stimulus of growth. The tap root
length was the more efficient parameter to compare root toxicity. The soaking of seeds
in the solution of aluminum did not affect the germination, root tap emission and the
growth of seedlings until 1280?M. With the increased of time of contact with the Al
solution, the young roots have been injured especially in papaya seedlings. The use of
stains pyrocatechol violet and hematoxylin were both efficient to determinate the
aluminum tolerance in papaya and passion fruit, but just pyrocatechol violet could
compare the doses used, produced a color gradient with increasing concentration of
aluminum. With the use of hematoxylin was only possible to separate the high
concentrations of low concentrations of aluminum. The best passion fruit cultivar was
IAC 273/277and papaya was Tainung<br>Os estudos da toler?ncia ao alum?nio em pl?ntulas de maracuj? (cvs. IAC-273/277, IACPaulista,
IAC-275, FB-100) e mam?o (cvs.Tainug, Golden, Gran Golden, Baixinho de
Santa Am?lia) foram realizados, em c?mara de crescimento nos Laborat?rios de
Qu?mica da Rizosfera e Laborat?rio de Analise de Sementes, Departamento de
Fitotecnia, Instituto de Agronomia da Universidade Federal Rural Rio de Janeiro.
Foram realizados experimentos com diferentes concentra??es de alum?nio em solu??o
nutritiva simples (com c?lcio) e completa, para analise do crescimento radicular
utilizando os par?metros comprimento radicular, taxa de crescimento radicular,
elonga??o radicular relativa, di?metro do colo, di?metro de ?pice da raiz principal bem
como testes com corantes. Foi tamb?m realizado estudos do efeito da embebi??o das
sementes com solu??es de alum?nio para verificar o efeito na porcentagem de
germina??o, pl?ntulas normais e anormais, e n?o germinadas. O uso da solu??o nutritiva
simples para realizar testes de curta dura??o de contacto ao alum?nio, n?o foi satisfat?rio
para mam?o, sendo mais adequado o uso de solu??o nutritiva completa. Em maracuj?,
ambas as solu??es podem ser utilizadas. As pl?ntulas de maracuj? crescidas em solu??o
simples com o aumento do tempo de contacto com alum?nio na solu??o, as ra?zes
ficaram endurecidas. Em concentra??es acima de 160?M de alum?nio, ocorreu efeito
fitotoxico, contudo em concentra??es menores que 80?M ocorreu at? aumento do
crescimento radicular para mam?o e maracuj?. O comprimento radicular foi o mais
eficiente par?metro indicador da toler?ncia ao alum?nio. A embebi??o das sementes em
alum?nio n?o afetou a germina??o a emiss?o da raiz principal e o crescimento da
pl?ntula at? a concentra??o da solu??o de embebi??o de 1280?M, mas a medida que
aumentou o tempo de contato e a concentra??o de alum?nio, as ra?zes rec?m emitidas
sofreram danos, principalmente as de pl?ntulas de mam?o. O uso dos corantes qu?micos
violeta de pirocatecol e hematoxilina foram eficiente na determina??o da toler?ncia ao
alum?nio em maracuj? e mam?o, mais somente o violeta de pirocatecol permitiu
comparar as doses entre si, gerando um gradiente de colora??o com o aumento da
concentra??o de alum?nio, com o uso da hematoxilina s? foi poss?vel separar as
concentra??es altas das concentra??es baixas de alum?nio. As melhores cultivares nas
condi??es testadas foi a IAC 273/277 de maracuj? e a cv Tainung de mam?o
Books on the topic "Seedling age"
1
Aldous, David E., and Ian H. Chivers. Sports Turf and Amenity Grasses. CSIRO Publishing, 2002. http://dx.doi.org/10.1071/9780643090019.
Full textAbstract:
Sports Turf and Amenity Grasses is a comprehensive reference for anyone involved with the selection and maintenance of grasses used in sports and amenity areas in all areas. It provides a means to identify these grasses through keys, descriptions and photographs, and also provides detailed information on sowing, oversowing, stolonising and mowing heights. 
 The performance of each grass is assessed and detailed comments made on positive and negative aspects of its use. A grass’s tolerance to high temperature, frost, drought, shade, wet soil, salinity, low soil fertility, wear and close mowing is given in a table with each aspect rated. Further comments are made on how well it combines with particular grasses and on issues such as seedling vigour and sowing times.
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Dunphy, Mark, Steve McAlpin, Paul Nelson, Michelle Chapman, and Hugh Nicholson. Australian Rainforest Seeds. CSIRO Publishing, 2020. http://dx.doi.org/10.1071/9781486311514.
Full textAbstract:
Have you ever wondered how to grow your own rainforest trees? Is there a beautiful tree that you have always wanted to collect and propagate the seed from? Are you in the business of ecological restoration, rainforest propagation or environmental education? 
 This long-awaited guide to rainforest seed propagation unlocks the secrets to growing 300 rainforest species. Providing specific information on how to sustainably collect, process and germinate seeds, this user-friendly book aims to support a growing movement of rainforest restoration. 
 With invaluable information based on 30 years of research in northern New South Wales, users will find even difficult rainforest species delightfully easy to grow. Seeing a seed germinate, caring for the seedling and eventually planting the tree is deeply satisfying. And, in this time of widespread deforestation, millions of trees are needed for restoration and every tree counts. Whether you are growing one or one hundred thousand, why not start today?
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Szewczyk, Janusz. Rola zaburzeń w kształtowaniu struktury i dynamiki naturalnych lasów bukowo-jodłowo-świerkowych w Karpatach Zachodnich. Publishing House of the University of Agriculture in Krakow, 2018. http://dx.doi.org/10.15576/978-83-66602-35-9.
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The aim of the study was to determine the influence of different disturbances (both natural and anthropogenic) on species composition and stand structure of old-growth mixed mountain forests in the Western Carpathians. These stands are usually dominated by beech, fir and spruce, mixed in different proportions. The tree main species represent different growth strategies, and they compete against each other. The longevity of trees makes the factors influencing the stand structure difficult to identify, even during longitudinal studies conducted on permanent research plots. That is why dendroecological techniques, based upon the annual variability of tree rings, are commonly used to analyze the disturbance histories of old-growth stands. Dendroecological methods make it possible to reconstruct the stand history over several centuries in the past by analyzing the frequency, intensity, duration and spatial scale of disturbances causing the death of trees. Combining the dendroecological techniques with the detailed measurements of stand structure, snag volume, CWD volume, and the analyses of regeneration species composition and structure allows us to identify the factors responsible for the changes in dynamics of mixed mountain forests. Various disturbance agents affect some species selectively, while some disturbances promote the establishment of tree seedlings of specific species by modifying environmental conditions. Describing the disturbance regime requires a broad scope of data on stand structure, on dead wood and tree regeneration, while various factors affecting all the stages of tree growth should be taken into consideration. On the basis of the already published data from permanent sample plots, combined with the available disturbance history analyses from the Western Carpathians, three research hypotheses were formulated. 1. The species composition of mixed mountain forests has been changing for at least several decades. These directional changes are the consequence of simultaneous conifer species decline and expansion of beech. 2. The observed changes in species composition of mixed mountain forests are the effect of indirect anthropogenic influences, significantly changing tree growth conditions also in the forests that are usually considered natural or near-natural. Cumulative impact of these indirect influences leads to the decrease of fir share in the tree layer (spruce decline has also been observed recently),and it limits the representation of this species among seedlings and saplings. The final effect is the decrease of fir and spruce share in the forest stands. 3. Small disturbances, killing single trees or small groups of trees, and infrequent disturbances of medium size and intensity dominate the disturbance regime in mixed mountain forests. The present structure of beech-fir-spruce forests is shaped both by complex disturbance regime and indirect anthropogenic influences. The data were gathered in permanent sample plots in strictly protected areas of Babia Góra, Gorce, and Tatra National Parks, situated in the Western Carpathians. All plots were located in the old-growth forest stands representing Carpathian beech forest community. The results of the measurements of trees, snags, coarse woody debris (CWD) and tree regeneration were used for detailed description of changes in the species composition and structure of tree stands. Tree ring widths derived from increment cores were used to reconstruct the historical changes in tree growth trends of all main tree species, as well as the stand disturbance history within the past two to three hundred years. The analyses revealed complex disturbance history in all of the three forest stands. Intermediate disturbances of variable intensity occurred, frequently separated by the periods of low tree mortality lasting from several decades up to over one hundred years. The intervals between the disturbances were significantly shorter than the expected length of forest developmental cycle, in commonly used theories describing the dynamics of old-growth stands. During intermediate disturbances up to several dozen percent of canopy trees were killed. There were no signs of stand-replacing disturbances, killing all or nearly all of canopy trees. The periods of intense tree mortality were followed by subsequent periods of increased sapling recruitment. Variability in disturbance intensity is one of the mechanisms promoting the coexistence of beech and conifer species in mixed forests. The recruitment of conifer saplings depended on the presence of larger gaps, resulting from intermediate disturbances, while beech was more successful in the periods of low mortality. However, in the last few decades, beech seems to benefit from the period of intense fir mortality. This change results from the influence of long-term anthropogenic disturbances, affecting natural mechanisms that maintain the coexistence of different tree species and change natural disturbance regimes. Indirect anthropogenic influence on tree growth was clearly visible in the gradual decrease of fir increments in the twentieth century, resulting from the high level of air pollution in Europe. Synchronous decreases of fir tree rings’ widths were observed in all three of the sample plots, but the final outcomes depended on the fir age. In most cases, the damage to the foliage limited the competitive abilities of fir, but it did not cause a widespread increase in tree mortality, except for the oldest firs in the BGNP (Babia Góra National Park) plot. BGNP is located in the proximity of industrial agglomeration of Upper Silesia, and it could be exposed to higher level of air pollution than the other two plots. High level of fir regeneration browsing due to the deer overabundance and insufficient number of predators is the second clear indication of the indirect anthropogenic influence on mixed mountain forests. Game impact on fir regeneration is the most pronounced in Babia Góra forests, where fir was almost completely eliminated from the saplings. Deer browsing seems to be the main factor responsible for limiting the number of fir saplings and young fir trees, while the representation of fir among seedlings is high. The experiments conducted in fenced plots located in the mixed forests in BGNP proved that fir and sycamore were the most preferred by deer species among seedlings and saplings. In GNP (Gorce National Park) and TNP (Tatra National Park), the changes in species composition of tree regeneration are similar, but single firs or even small groups of firs are present among saplings. It seems that all of the analysed mixed beech-fir-spruce forests undergo directional changes, causing a systematic decrease in fir representation, and the expansion of beech. This tendency results from the indirect anthropogenic impact, past and present. Fir regeneration decline, alongside with the high level of spruce trees’ mortality in recent years, may lead to a significant decrease in conifers representation in the near future, and to the expansion of beech forests at the cost of mixed ones.
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Clark, Samuel. Good Lives. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780198865384.001.0001.
Full textAbstract:
Reasoning with autobiography is a way to self-knowledge. We can learn about ourselves, as human beings and as individuals, by reading, thinking through, and arguing about this distinctive kind of text. Reasoning with Edmund Gosse’s Father and Son is a way of learning about the nature of the good life and the roles that pleasure and self-expression can play in it. Reasoning with Siegfried Sassoon’s Memoirs is a way of learning about transformative experience, self-alienation, and therefore the nature of the self. Good Lives develops and defends this claim, by answering a series of questions. What is an autobiography? How can we learn about ourselves from reading one? On what subjects does autobiography teach? What should we learn about them? In particular, given that autobiographies are narratives, should we learn something about the importance of narrative in human life? Could our storytelling about our own lives make sense of them as wholes, unify them over time, or make them good for us? Could storytelling make the self? The overall aim of the book is a critique of narrative and a defence of a self-realization account of the self and its good. As it pursues that, the book investigates the wide range of extant accounts of the self and of the good life, and defends pluralist realism about self-knowledge by reading and reasoning with autobiographies of self-discovery, martial life, and solitude. It concludes: autobiography can be reasoning in pursuit of self-knowledge; each of us is an unchosen, initially opaque, seedlike self; our good is the development and expression of our latent capacities, which is our individual self-realization; self-narration plays much less role in our lives than some thinkers have supposed, and the development and expression of potential much more.
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Gleń-Karolczyk, Katarzyna. Zabiegi ochronne kształtujące plonowanie zdrowotność oraz różnorodność mikroorganizmów związanych z czernieniem pierścieniowym korzeni chrzanu (Atmoracia rusticana Gaertn.). Publishing House of the University of Agriculture in Krakow, 2019. http://dx.doi.org/10.15576/978-83-66602-39-7.
Full textAbstract:
Horseradish roots, due to the content of many valuable nutrients and substances with healing and pro-health properties, are used more and more in medicine, food industry and cosmetics. In Poland, the cultivation of horseradish is considered minor crops. In addition, its limited size causes horseradish producers to encounter a number of unresolved agrotechnical problems. Infectious diseases developing on the leaves and roots during the long growing season reduce the size and quality of root crops. The small range of protection products intended for use in the cultivation of horseradish generates further serious environmental problems (immunization of pathogens, low effectiveness, deterioration of the quality of raw materials intended for industry, destruction of beneficial organisms and biodiversity). In order to meet the problems encountered by horseradish producers and taking into account the lack of data on: yielding, occurrence of infectious diseases and the possibility of combating them with methods alternative to chemical ones in the years 2012–2015, rigorous experiments have been carried out. The paper compares the impact of chemical protection and its reduced variants with biological protection on: total yield of horseradish roots and its structure. The intensification of infectious diseases on horseradish leaves and roots was analyzed extensively. Correlations were examined between individual disease entities and total yield and separated root fractions. A very important and innovative part of the work was to learn about the microbial communities involved in the epidemiology of Verticillium wilt of horseradish roots. The effect was examined of treatment of horseradish cuttings with a biological preparation (Pythium oligandrum), a chemical preparation (thiophanate-methyl), and the Kelpak SL biostimulator (auxins and cytokinins from the Ecklonia maxima algae) on the quantitative and qualitative changes occurring in the communities of these microorganisms. The affiliation of species to groups of frequencies was arranged hierarchically, and the biodiversity of these communities was expressed by the following indicators: Simpson index, Shannon–Wiener index, Shannon evenness index and species richness index. Correlations were assessed between the number of communities, indicators of their biodiversity and intensification of Verticillium wilt of horseradish roots. It was shown that the total yield of horseradish roots was on average 126 dt · ha–1. Within its structure, the main root was 56%, whereas the fraction of lateral roots (cuttings) with a length of more than 20 cm accounted for 26%, and those shorter than 20 cm for 12%, with unprofitable yield (waste) of 6%. In the years with higher humidity, the total root yield was higher than in the dry seasons by around 51 dt · ha–1 on average. On the other hand, the applied protection treatments significantly increased the total yield of horseradish roots from 4,6 to 45,3 dt · ha–1 and the share of fractions of more than 30 cm therein. Higher yielding effects were obtained in variants with a reduced amount of foliar application of fungicides at the expense of introducing biopreparations and biostimulators (R1, R2, R3) and in chemical protection (Ch) than in biological protection (B1, B2) and with the limitation of treatments only to the treatment of cuttings. The largest increments can be expected after treating the seedlings with Topsin M 500 SC and spraying the leaves: 1 × Amistar Opti 480 SC, 1 × Polyversum WP, 1 × Timorex Gold 24 EC and three times with biostimulators (2 × Kelpak SL + 1 × Tytanit). In the perspective of the increasing water deficit, among the biological protection methods, the (B2) variant with the treatment of seedlings with auxins and cytokinins contained in the E. maxima algae extract is more recommended than (B1) involving the use of P. oligandrum spores. White rust was the biggest threat on horseradish plantations, whereas the following occurred to a lesser extent: Phoma leaf spot, Cylindrosporium disease, Alternaria black spot and Verticillium wilt. In turn, on the surface of the roots it was dry root rot and inside – Verticillium wilt of horseradish roots. The best health of the leaves and roots was ensured by full chemical protection (cuttings treatment + 6 foliar applications). A similar effect of protection against Albugo candida and Pyrenopeziza brassicae was achieved in the case of reduced chemical protection to one foliar treatment with synthetic fungicide, two treatments with biological preparations (Polyversum WP and Timorex Gold 24 EC) and three treatments with biostimulators (2 × Kelpak SL, 1 × Tytanit). On the other hand, the level of limitation of root diseases comparable with chemical protection was ensured by its reduced variants R3 and R2, and in the case of dry root rot, also both variants of biological protection. In the dry years, over 60% of the roots showed symptoms of Verticillium wilt, and its main culprits are Verticillium dahliae (37.4%), Globisporangium irregulare (7.2%), Ilyonectria destructans (7.0%), Fusarium acuminatum (6.7%), Rhizoctonia solani (6.0%), Epicoccum nigrum (5.4%), Alternaria brassicae (5.17%). The Kelpak SL biostimulator and the Polyversum WP biological preparation contributed to the increased biodiversity of microbial communities associated with Verticillium wilt of horseradish roots. In turn, along with its increase, the intensification of the disease symptoms decreased. There was a significant correlation between the richness of species in the communities of microbial isolates and the intensification of Verticillium wilt of horseradish roots. Each additional species of microorganism contributed to the reduction of disease intensification by 1,19%.
Book chapters on the topic "Seedling age"
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Asih, Pitri Ratna, Agus Wartapa, Mustakim Mustakim, and Sukiyanto Sukiyanto. "The Effect of Number and Age of TSS (True Shallot Seed) Seedling on Shallot Seed Production." In Proceedings of the International Symposium Southeast Asia Vegetable 2021 (SEAVEG 2021). Atlantis Press International BV, 2022. http://dx.doi.org/10.2991/978-94-6463-028-2_14.
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Lantican, Gaudencia A. "Field Screening of Gamma-Irradiated Cavendish Bananas." In Efficient Screening Techniques to Identify Mutants with TR4 Resistance in Banana. Springer Berlin Heidelberg, 2022. http://dx.doi.org/10.1007/978-3-662-64915-2_7.
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AbstractIn our search for Cavendish bananas to withstand Fusarium oxysporum f. sp. cubense (Foc TR4) and other diseases, field screening of tissue-cultured Grand Nain banana seedlings derived from gamma-irradiated shoot tips was explored. Six months after irradiation and multiplication in the laboratory, the plantlets (M1V6) were individually grown in seedling bags under screen house conditions for 8 weeks, side-by-side with non-irradiated plantlets of the same clone. Once acclimatized, the banana plants were grown in an area confirmed positive of Foc TR4 (based on previous farm records stating that more than 50% of the plant population succumbed to the disease). Seedlings from each treatment (dose of radiation) were divided into four replicates, regardless of the number of plants. Each plant was given a unique identification code for traceability during disease monitoring, bunch and fruit quality evaluation.Incidences of Foc TR4, Moko disease (Ralstonia solanacearum) and virus diseases were monitored weekly. Plants found positive of any disease were eradicated immediately. The plant population for the succeeding generation was managed by removing the unwanted suckers, 12 weeks from planting using a spade gouge and keeping only one sucker per plant for the next generation. Agronomic characters of each plant were taken at the flowering stage. These included age to flower, height, pseudostem circumference, number of leaves and height of the sucker. The bunch was harvested 12 weeks from flowering. The number of hands in a bunch, the number of fingers and weight of a hand were recorded. The same agronomic characters of the plant were taken for the succeeding generations.Plants left standing in the field without any disease symptoms 3 years after planting were considered as putative mutants and were selected as candidate lines for multiplication and second-generation field screening. Only healthy suckers (free from viruses) were further multiplied via tissue culture technique to reach M1V6. Clean suckers from each line free of soil debris or dirt were sent to the laboratory for multiplication. At least 1000 plantlets were produced from each line for the second-generation field screening. These were grown in two locations – with and without records of Foc TR4. Field monitoring activities including plant population management, disease incidence assessment and fruit quality evaluation were carried out following the same protocols used in the establishment of the first-generation plants. Lines with population showing ≤10% Foc TR4 after the first harvest, with good vigor, fruit quality and productivity were considered as candidates for further multiplication, farmers distribution and field planting under semi-commercial scale.
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Kärkkäinen, Katri, Sonja T. Kujala, Rosario Garcia-Gil, et al. "Genetic Effects." In Managing Forest Ecosystems. Springer Nature Switzerland, 2024. https://doi.org/10.1007/978-3-031-70484-0_7.
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Abstract Genetic effects of continuous cover forestry (CCF) are not well known. We need more research, especially on the genetics of spruce-dominated CCF sites. Levels of relatedness are of interest, as are estimates of safe limits for the intensity and duration of CCF practices that secure genetic potential for good growth and quality. With even-aged forestry, genetically improved regeneration material can be used to mitigate climate change-related risks through breeding and deployment recommendations. In CCF, currently based on natural regeneration, we assume that enough seedlings establish, and that sites contain enough genetic variation to enable natural selection and evolutionary processes. Based on research in other regions, the number of reproducing trees must be kept large to avoid excessive levels of relatedness and inbreeding and to maintain sufficient levels of genetic diversity. In some well-documented long-term experiments in other regions, intensive high-grading has led to slower growth rates, which could partly be due to genetic degradation of the stand. If contemporary recommendations for selection cutting are followed, negative genetic effects should be unlikely.
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M. Andrew, Samora, Siwa A. Kombo, and Shabani A.O. Chamshama. "Germination and Seedling Growth of Entandrophragma bussei Harms ex Engl. from Wild Populations." In Vegetation Index and Dynamics. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.97489.
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Entandrophragma bussei Harms ex Engl. (wooden banana) is an important indigenous multipurpose tree species endemic to Tanzania. The species has a long history of human use but recent increased utilization pressure, deforestation and high mortality rate of seedlings threaten the survival of natural populations in the wilderness. Therefore, to facilitate domestication, two experimental studies were conducted to evaluate variations in seed germination and seedling growth of three wild populations at the Directorate of Tree Seed Production Laboratories in Morogoro, Tanzania. Germination percentage, mean germination rate, final germination rate and germination index varied significantly among the populations. In terms of seedling growth there was a significant difference in number of leaves among the populations at 3 months of age. The number of course roots and seedling shoot fresh weight varied significantly among the studied populations at 10 months of age. Ruaha population had the highest survival (56%) followed by Kigwe (41%) and Tarangire being the last (36%). The two experiments have clearly demonstrated the existence of considerable variation in germination and seedling growth traits in E. bussei. These traits may prove to be important tools for selection of suitable seed sources for domestication and tree improvement programmes.
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O. Agele, Samuel, Friday E. Charles, Appolonia E. Obi, and Ademola I. Agbona. "Oil Palm-Based Cropping Systems of the Humid Tropics: Addressing Production Sustainability, Resource Efficiency, Food Security and Livelihood Challenges." In Elaeis guineensis. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.98257.
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The oil palm (Elaeis guineensis Jacq), is a crop of tremendous food, nutrition and economic importance in the tropics. Weather variability and extremes profoundly impact the establishment, survival and productivity of oil palm on the field. Alleys of palm trees in plantation are cropped with arables during early years following field establishment. Studies were conducted at the Nigerian Institute for Oil Palm Research, Benin City, Nigeria. Oil palm seedlings responded to shading, irrigation and AMF inoculation via enhanced water use efficiency, growth vigor and reduced seedling mortality in the nursery during dry season. Age of oil palm and intercrops of Cassava, Maize and Pepper affected mixture productivity and competitive functions in alleys of 2 to 6 years old oil palm fields. Fertilizers (inorganic/organic) promoted agronomic and physiological efficiencies of N use by alley species. Sole crops had higher N use efficiency compared with the intercrops across the fertilizers.
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Duan, Jie, and Dilnur Abduwali. "Basic Theory and Methods of Afforestation." In Silviculture. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96164.
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Afforestation is an important practice in silviculture. This chapter outlines the forest site, site preparation, selection of afforestation materials in the process of afforestation. The life cycle of forests is very long, and it is difficult to change them once afforested. Therefore, the forest site must be analyzed in depth before afforestation to maintain the success of afforestation and the healthy growth of forests later. Forest sites are mainly affected by environmental and human activities. To facilitate afforestation, it is necessary to evaluate and classify the forest site factors and achieve a suitable species planted on the right site. Site preparation is also based on site classification. It is usually carried out after determining the type of afforestation land, divided into mechanical land preparation and chemical methods. An essential task of site preparation is to maintain soil moisture and promote seedlings’ survival and growth. Afforestation materials are mainly divided into three categories: seed, seedling, and cutting. The choice of these three types of afforestation materials and methods is related to site conditions, tree species, and age.
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Sisk, Cheryl L., and Russell D. Romeo. "Remodeling the Adolescent Brain." In Coming of Age. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780195314373.003.0003.
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Chapter 3 covers the basic neural mechanisms by which the brain undergoes an extreme makeover during adolescence. It starts with the proposition that the nervous system has only so many tools in the toolbox to accomplish this makeover and these tools can be categorized as either progressive or regressive. Progressive tools include neurogenesis, migration, axon outgrowth, and synapse formation. Regressive tools include programmed cell death and experience-dependent synapse elimination. Two analogies are used to help readers understand this process: house remodeling and gardening. These analogies are woven into the concepts of progressive and regressive developmental events, and they can be imagined as mechanisms that result in either gain or loss of function (e.g., a house addition might equal new neurons or new projections) or maximize efficiency and success (pruning of seedlings might equal programmed cell death). Research on increased myelination during adolescence is also discussed.
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Varier, M. R. Raghava. "The Age of the Samhitas." In A Brief History of Āyurveda. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190121082.003.0003.
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The systematic and codified knowledge of Āyurveda attained maturity in the classical texts of the samhitas. They are several texts and each of them is attached to the name of an ācārya, preceptor, such as Caraka, Suśruta, Bhela, Kāśyapa, and Hārīta. The knowledge and wisdom of indigenous healing and healthcare are explained in the samhitas with special references to a particular branch of the system of medicine. Thus kāyacikitsa, general medicine, is the subject of the Carakasamhita while śalyacikitsa, surgery, is the subject of the Suśrutasamhita. Bhēḷasamhita deals mainly with diseases and treatments for the mind, Kāśyapasamhita focuses on koumārabhṛtya, pediatrics, and the subject of the Hārītasamhita is gṛhabādha, demonology, and allied matters. What were preserved in preceding literature including the Vedas, the Brāhmaņas, and the Buddhist Pali canonical texts as seeds and seedlings are found fully grown in the samhitas, nourished by scholarly discussions at various levels. The indigenous medical system was designated as Āyurveda by the time of the samhitas. Topics such as qualities of a preceptor, qualities of a disciple, and qualities of the science are discussed in the various samhitas. Initiation of the disciples, knowledge of anatomy, procedure of treatment, and Modalities of treatment are discussed in great detail. The traditional method of the daivavyapāśraya (the divine or magico-religious) mode of treatment of the Vedic tradition was replaced by the yuktivyapāśraya (empirico-rational) method of therapy with the codification of the Carakasamhita. The emphasis of Caraka was on the process of investigation, which is essential for arriving at scientific truth and hence he repeatedly uses the word parīkṣa instead of pramāṇa.
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Burch, William R., Gary E. Machlis, and Jo Ellen Force. "An Overview of the Model." In The Structure and Dynamics of Human Ecosystems. Yale University Press, 2017. http://dx.doi.org/10.12987/yale/9780300137033.003.0002.
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This chapter examines the Human Ecosystem Model (HEM), which began as a seedling in the late 1960s and has grown and developed into a middle-aged forest today. Human ecosystem is defined as a coherent system of biophysical and social factors capable of adaptation and sustainability over time. Coherence is relative and varying within human ecosystems. There can be “tight coherence” between available energy flows and economic activity, as when a scarcity of petroleum reduces industrial production and raises costs. There can also be “loose coherence,” such as the relationship between available water supplies and the performance of educational institutions. The chapter also elaborates on some of the other key words from the given definition of human ecosystem, such as capability, adaptation, and sustainability.
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Nunes, Henriqueta da Conceição Brito, Luiz Fernandes Silva Dionisio, Manoel Tavares de Paula, et al. "GROWTH ANALYSIS IN PRE-GERMINATED AÇAÍ TREE SEEDLINGS (Euterpe oleracea Mart. - Arecaceae) - CULTIVAR CHUMBINHO." In From Knowledge to Innovation: The Multidisciplinary Journey. Seven Editora, 2025. https://doi.org/10.56238/sevened2025.001-007.
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The açaí palm ( Euterpe oleracea Mart.) is a palm tree native to the Amazon floodplains, with increasing relevance in the national and international market, which has generated greater interest in its cultivation. Currently, the extractive exploitation of the açaí palm has been partially replaced by agricultural crops on dry land, indicating the need for studies related to the species. In a seedbed of the Municipal Secretariat of Agriculture and Rural and Economic Development (SEMADRE) of Cametá-PA, the growth analysis of the species E. oleracea (chumbinho) was carried out using the following parameters: stem height, radicle length, wet weight, dry weight, moisture content and absolute growth rate (AGR). After the 45th day of sowing, four collections (treatments) of plants were carried out in the following periods: five (5), ten (10), fifteen (15) and twenty-five (25) days after emergence in seedbed. In each period, 30 plants/treatment (time) were randomly collected, with 10 seedlings per replicate. The samples were analyzed at Campus XVIII of the State University of Pará. The seedlings, without seeds, were measured, weighed and dried in an oven at 80°C for 24 to 36 hours, until they reached constant weight. Most of the seeds showed aerial emergence after 30 days, in the so-called stick stage, with height ranging from 2.5 to 7.7 cm. In the first treatment (5 days), the average values recorded were: radicle length of 5.43 cm, stem height of 5.81 cm, wet weight of 0.43 g and dry weight of 0.09 g. The ACR was 0.004 g.day⁻¹, indicating the average growth rate. Based on the stem length, adjusted by linear regression, the ideal time to transplant the seedlings into polyethylene bags was estimated at 75.58 days. These results contribute to optimizing the management of dry land cultivation.
Conference papers on the topic "Seedling age"
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Nuntanart, Kunjira, Voravit Jaituy, and Papis Wongchaisuwat. "Factors Affecting Oil Palm Cultivation Using Machine Learning and Statistical Inference Methods." In 14th International Seminar on Industrial Engineering and Management. Trans Tech Publications Ltd, 2025. https://doi.org/10.4028/p-bxilf6.
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Oil palm has become the world’s leading vegetable oil with a tremendous increase in plantations and production. Thailand is among the three largest producers of oil palm. To enhance the oil palm producing potential competitively, the oil palm industry in Thailand has to improve the efficiency of production management among Thai farmers. This work aimed to identify important factors affecting oil palm cultivation based on machine learning and statistical inference methods. The proposed models were evaluated on a data set collected from the local community group for oil palm cultivation and production in Surat Thani and Nakhon Si Thammarat provinces, Thailand. The seedlings’ source and the age of oil palm seedlings were the most significant features according to the analysis.
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Zhang, Hao. "Effect of seedling age on the ovipositon and performance of Hessian fly (Mayetiola destructor) on wheat." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.114209.
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Handayani, Valentina Dwi Suci, I. Gusti Bagus Budi Dharma, Fathi Alfinur Rizqi, Najmu Tsaqib Akhda, and Iman Sabarisman. "Implementation of Coconut Waste Processing Technology to Support Agricultural Sustainability in Coastal Tourism Areas." In 3rd International Conference on Community Engagement and Education for Sustainable Development. AIJR Publisher, 2023. http://dx.doi.org/10.21467/proceedings.151.50.
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Beach tourism is identical to coconut. Almost all beach tourists will look forward to enjoying fresh coconut water under the hot beach atmosphere. High coconut consumption in tourist areas greatly benefits the economy of traders in tourist areas. On the other hand, it creates a problem due to increased coconut waste. Coconut waste is large and difficult to decompose, resulting in a buildup that could disrupt coastal tourism. Goa Cemara Beach in Bantul, Yogyakarta, is one of the areas affected by coconut waste accumulation, hence warranting proper management of coconut shell waste. Coconut shell waste Management is expected to be a new source of income for the local community. Community service activities are carried out to apply coconut waste processing technology. This technology is carried out to overcome the problem of accumulation of waste and utilize waste as a support for sustainable agriculture. Applying this waste treatment technology involves two community groups, namely the “Pantai Goa Cemara” tourism awareness group and the “Tani Raharjo” farmer's group. Each group has a synergistic role in the processing and utilization of waste. The Goa Cemara Beach tourism awareness group, processes the destruction of coconut shell waste with a mill. The crushed coconut shell waste will produce small pieces. Sorting the crushed coconut waste will produce two forms, namely cocopeat, and cocofiber. Laboratory tests are carried out to see the content of cocopeat and the safe amount that can be applied to agriculture. Laboratory results showed organic matter 19.51-28.70%, Nitrogen 0.69-0.88%, Phosphorus 0.40-0.58%, Potassium 0.26-0.33%, and pH 7.66-7.95 depending on the age of the waste. Community service activities are carried out to utilize cocopeat to become an environmentally friendly seedling medium. Seedling media with cocopeat printed in squares can sow plant seeds. This box media is often called a soil block and does not require small plastic pots for seeds. Thus, it can reduce plastic waste on agricultural land. In addition, the utilization of processed coconut shell waste can support sustainable agriculture.
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Temel, Fatih. "Assisted Migration of Pinus brutia in Türkiye: A Potential Tool for Sustaining Growth in the Face of Climate Change." In 3rd International Congress on Engineering and Life Science. Prensip Publishing, 2023. http://dx.doi.org/10.61326/icelis.2023.34.
Full textAbstract:
Forest tree populations deal with climate change either by increasing frequency of alleles contributing to adaptation to new conditions through natural selection or by migrating to places where they can establish and survive. In order for either mechanism to work, changes in allele frequencies or rate of migration should be able to keep up with the rate of climatic changes. For most forest tree populations, however, rate of climate change is faster than their genetic adaptation or migration rates. One potential solution to this problem is human assisted migration of forest tree species and involves moving forest tree species or seed sources of a forest tree species into areas where they would be better adapted to future climatic conditions than the local species or seed source. Pinus brutia is the most important forest tree species in Türkiye, covering 5.1 million ha (23% of total forests), and accounting for 9.3 million m3 (34%) of annual timber production. Over 50 million P. brutia seedlings are produced annually (~20% of total forest tree seedling production). Current seed transfer is based on the country’s six current seed zones, developed in the absence of provenance test data, are based on relative humidity during the vegetation period, and are partitioned into two to six sub-zones within each main zone (22 in total) on the basis of the length of vegetation period. Most of the P. brutia range in Türkiye is located in places where the effects of climate change are prominent. In 1988, a comprehensive provenance testing program was initiated where 50 P. brutia populations from Türkiye and Northern Cyprus were tested on 26 sites in Türkiye and Northern Cyprus. Trees in these tests were measured for survival, growth and form at ages three, five, 10 and 20. We used population mean growth data from these provenance tests to develop transfer functions from which safe seed transfer distances were calculated. On average, DBH at age 20 (DBH20) had the strongest relationship with the transfer distances. For each site, growth relative to local population was calculated and plotted across all climatic transfer distances for all sites. Transfer distances for summer precipitation (PPT_sm), mean warmest month temperature (MWMT) and annual heat moisture index (AHM) were found to have significant relationship with DBH20. P. brutia seed sources can be transferred within 105 mm PPT_sm, 10 °C MWMT and 36 units AHM without sacrificing volume growth more than 5% compared to that of local seed source. Provenance test data can be used to determine suitable seed sources for a given plantation site for different future climatic condition scenarios. This approach can help sustaining growth in P. brutia plantations in the face of climate change.
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Hao, Yi, Ze-Tian Zhang, Yu-Kui Rui, et al. "Effect of Different Nanoparticles on Seed Germination and Seedling Growth in Rice." In 2nd Annual International Conference on Advanced Material Engineering (AME 2016). Atlantis Press, 2016. http://dx.doi.org/10.2991/ame-16.2016.28.
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Certan, Corina, and Constantin Bulimaga. "Dinamica indicilor dendrometrici a speciilor lemnoase de salcâm, ulm și frasin din cariera de calcar „Lafarge Ciment” din Rezina." In Provocări şi tendinţe actuale în cercetarea componentelor naturale şi socio-economice ale ecosistemelor urbane şi rurale. Institute of Ecology and Geography, Republic of Moldova, 2020. http://dx.doi.org/10.53380/9789975891608.15.
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Dynamics of growths in the height and after the diameter of the seedlings, of acacia, elm and ash, had investigated on the freshly formed sterile dump limestone quarry „Lafarge Ciment”. In the first year after planting, the young seedlings, had an increase in height and in diameter slow and uneven. In the years that followed, the seedlings became more viable and less influenced by local and temporal fluctuations of environmental factors. The offspring of the woody species had a sufficiently high (78.8-99.5%).
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MIEZĪTE, Olga, Jeļena RŪBA, Lāsma FREIMANE, Imants LIEPA, and Edgars DUBROVSKIS. "THE HEALTH STATUS AND NATURAL REGENERATION OF PINUS SYLVESTRIS L. AFTER THE SURFACE FIRE IN VACCINIOSA FOREST TYPE IN LATVIA." In RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.100.
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From abiotic factors the most effecting influence on forest ecosystems has fire. Two years after surface fire in the pine stands growing in Vacciniosa forest type. Two PL (hereinafter PL) were installed in medium-aged (49 years old, 2.3 ha) and two PLs - in maturing (96 years old, 2.5 ha) stands. In each PL (20x20 m), the numbering of the trees was carried out and their placement was fixed, as well as the diameter, height and height of the green crown were measured. The sanitary condition of each tree was evaluated. For registration of one-year and two-year seedlings in each sample plot 25 sampling units (1 m2) were used. The similar sampling units were used for evaluation of ground cover (5 in each PL diagonally arranged), the obtained samples were weighed. The purpose of the study was to analyze the health status and natural regeneration of P.sylvestris after the surface fire. The ground vegetation was completely burned out in the medium-aged stand, but in the maturing stand both ground vegetation and organic layer - mosaically. The average burning height of trees in the medium-aged forest stand was 0.6±0.64 m, in the maturing stand - at 2.3±0.34 m. The natural regeneration was not detected in the first year after surface fire in the medium-aged forest (only 58800 one-year seedlings were recorded at the second year after fire), while in the maturing stand it was at this time (46600 one-year and 14200 two-year seedlings). Insect damage and cracked bark was not detected.
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Muratov, Shukrullo, Shavkat Hasanov, Khusniddin Pardaev, and Fotima Saydullaeva. "Economic assessment of factors affecting income from the activities of household farms in rural areas: a case of Samarkand province." In 23rd International Scientific Conference. “Economic Science for Rural Development 2022”. Latvia University of Life Sciences and Technologies. Faculty of Economics and Social Development, 2022. https://doi.org/10.22616/esrd.2022.56.053.
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The study examines the specifics of household (Tomorka) farms, the role and importance of income from household (Tomorka) farms activities in rural areas, economic assessment of the factors affecting income from activities. The factors influencing the formation of income from business activities were economically assessed using the Tobit model, and a VIF (Variance inflation factor) test was conducted to determine their multicollinearity. The age of landowners, the amount of arable land, the cost of organic and mineral fertilizers, the cost of seeds and seedlings, the cost of preparing the land for planting, and the cost of land and household services impact the increase in income from the household activities, and <.01) was found to be statistically significant. It was scientifically based on the data of landowners, the presence of family members aged 0-3 years, the satisfaction of landowners with water supply in the irrigation of arable land at a statistical significance of 5% (p <.05). The results were showing that scientifically based proposals have been developed to increase the income of the rural population from the household (Tomorka) farm activities.
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McGrath, J. Mitchell, and Suba Nagendran. "Discovery of resistance to seedling disease caused by Rhizoctonia solani AG2-2, description of the host-pathogen interaction, and development of a seedling disease screening nursery." In American Society of Sugar Beet Technologist. ASSBT, 2007. http://dx.doi.org/10.5274/assbt.2007.55.
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Tolbina, I., and Mikhail Chernyshov. "THE CURRENT INTENSITY OF THE GROWTH OF SCOTS PINE CROPS IN THE KHRENOVSKY FOREST." In LANDSCAPE ARCHITECTURE – FROM THE SOURCE TO INNOVATION. FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov, 2024. https://doi.org/10.58168/landscape2024_195-199.
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The main problem of preserving biodiversity in the forest fund is the implementation of environmental monitoring with the study of the species structure of forest plantations, intraspecific, form and genetic diversity of the main forest-forming species. In order to determine the level of diversity and its dynamics, it is necessary to study artificial pine plantations throughout their entire life. The level of individual, intraspecific and genetic variability in regional and local populations is directly related to their adaptive ability to changing environmental conditions, resistance to pests and diseases, thereby determining the viability and longevity of each tree. Scots pine (Pinus sylvestris L.) is a widespread and economically valuable forest coniferous species, the planted area of which in the forest fund of the Russian Federation is 119,493.1 thousand hectares. Historically, the forests of the Khrenovsky pine forest are represented by single- and multi-aged, single- and multi-tiered, simple and complex plantings of artificial and natural origin, which are dominated by Scots pine. Over the years, they have all been the objects of diverse scientific research. Comprehensive studies in middle-aged and ripening forest plantations of Scots pine, created by hand planting 2-year-old seedlings with an open root system under a shovel or Kolesov's sword and growing in specially protected natural areas in Khrenovsky Bor, are fully consistent with the directions of research work of the Federal State Budgetary Educational Institution of Higher Education «VSFLTU named after G.F. Morozova».
Reports on the topic "Seedling age"
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Israel, Alvaro, and John Merrill. Production of Seed Stocks for Sustainable Tank Cultivation of the Red Edible Seaweed Porphyra. United States Department of Agriculture, 2006. http://dx.doi.org/10.32747/2006.7696527.bard.
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Porphyra species (commonly known as ‘nori’ or ‘purple laver’) are edible red seaweeds rich in proteins, vitamins and other highly valued biogenic compounds. For years Porphyra has been cultured using seeded nets extended in the open sea, and its biomass consumed primarily in the Far East. While demands for international markets have increased steadily at an average of 20% per year, supplies are on the verge and not expected to meet future demands. Alternatively, land-based cultivation of seaweed has become attractive in the mariculture industry since (1) important growth parameters can be controlled, (2) is environmentally friendly and (3) perfectly matches with integrated aquaculture leading to sustainable, high quality products. During the last few years a tank cultivation technology for Porphyra has been developed at the Israeli institution. This technology is based on indoor production of asexual spores and their subsequent growth to 1-2 mm seedlings. The seedlings are then transferred to outdoor tanks and ponds when seawater temperatures drop to 20 °C, or below, and days become shorter during winter time. However, the current technology efficiently serves only about 100 m2 of ponds during one growth season. In order to produce seedlings in sufficient amounts, it is critical to address both technical and biological aspects of seedling production, securing optimal up-scale to commercial-size cultivation farms. We hypothesize that massive production of spores is related to thalli origin, thalli age and sporulation triggers, and that seedling survival and their subsequent growth potential is determined by the seawater quality and overall indoor growth conditions imposed. A series of bio-reactors were constructed and tested in which spore release and spore growth were separately studied. The main assessment criteria for optimal viability of the seedlings will be by determining their electron transport rate using PAM fluorometry and by subsequent growth and biomass yields in outdoor ponds. Altogether the project showed (1), controlled sporulation is possible in big outdoor/growth chamber settings provided initial stock material (small frozen seedlings) is at hand, (2), contamination problems can be almost completely avoided if stock material is properly handled (clean as possible and partially dehydrated prior to freezing), (3), spore release can significantly be enhance using high nutrient levels during thawing for P. yezoensis and P. haitanensis, but not for P. rosengurttii, (4), PAM fluorometry is an efficient tool to estimate growth capacity in both seedlings and juvenile thalli. The BARD funding also served to explore other aspects of Porphyra biology and cultivation. For example, the taxonomical status of Porphyra strains used in this study was defined (see appendix), and the potential use of this seaweed in bioremediation was well substantiated. In addition, BARD funding supported a number of opportunities and activities in the Israeli lab, direct or indirectly related to the initial objectives of the project such as: additional molecular work in other seaweeds, description of at least 2 new species for the Israeli Mediterranean, and continuous support for the writing of a book on Global Change and applied aspects of seaweeds. The technology for Porphyra cultivation in land-based ponds is readily available. This study corroborated previous know-how of Porphyra growth in tanks and ponds, and yet offers important improvements regarding seedling production and their handling for successful cultivation. This study supported various other activities opening additional important issues in the biology/cultivation/use of Porphyra and other seaweeds.
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Chamovitz, Daniel, and Albrecht Von Arnim. Translational regulation and light signal transduction in plants: the link between eIF3 and the COP9 signalosome. United States Department of Agriculture, 2006. http://dx.doi.org/10.32747/2006.7696515.bard.
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The COP9 signalosome (CSN) is an eight-subunit protein complex that is highly conserved among eukaryotes. Genetic analysis of the signalosome in the plant model species Arabidopsis thaliana has shown that the signalosome is a repressor of light dependent seedling development as mutant Arabidopsis seedlings that lack this complex develop in complete darkness as if exposed to light. These mutant plants die following the seedling stage, even when exposed to light, indicating that the COP9 signalosome also has a central role in the regulation of normal photomorphogenic development. The biochemical mode of action of the signalosome and its position in eukaryotic cell signaling pathways is a matter of controversy and ongoing investigation, and recent results place the CSN at the juncture of kinase signaling pathways and ubiquitin-mediated protein degradation. We have shown that one of the many CSN functions may relate to the regulation of translation through the interaction of the CSN with its related complex, eukaryotic initiation factor (eIF3). While we have established a physical connection between eIF3 subunits and CSN subunits, the physiological and developmental significance of this interaction is still unknown. In an effort to understand the biochemical activity of the signalosome, and its role in regulating translation, we originally proposed to dissect the contribution of "h" subunit of eIF3 (eIF3h) along the following specific aims: (i) Isolation and phenotypic characterization of an Arabidopsis loss-of-function allele for eIF3h from insertional mutagenesis libraries; (ii) Creation of designed gain and loss of function alleles for eIF3h on the basis of its nucleocytoplasmic distribution and its yeast-two-hybrid interactions with other eIF3 and signalosome partner proteins; (iii) Determining the contribution of eIF3h and its interaction with the signalosome by expressing specific mutants of eIF3h in the eIF3h- loss-of function background. During the course of the research, these goals were modified to include examining the genetic interaction between csn and eif3h mutations. More importantly, we extended our effort toward the genetic analysis of mutations in the eIF3e subunit, which also interacts with the CSN. Through the course of this research program we have made several critical scientific discoveries, all concerned with the apparent diametrically opposed roles of eIF3h and eIF3e. We showed that: 1) While eIF3e is essential for growth and development, eIF3h is not essential for growth or basal translation; 2) While eIF3e has a negative role in translational regulation, eIF3h is positively required for efficient translation of transcripts with complex 5' UTR sequences; 3) Over-accumulation of eIF3e and loss-of-function of eIF3h both lead to cop phenotypes in dark-grown seedlings. These results were published in one publication (Kim et al., Plant Cell 2004) and in a second manuscript currently in revision for Embo J. Are results have led to a paradigm shift in translation research – eIF3 is now viewed in all systems as a dynamic entity that contains regulatory subuits that affect translational efficiency. In the long-term agronomic outlook, the proposed research has implications that may be far reaching. Many important plant processes, including developmental and physiological responses to light, abiotic stress, photosynthate, and hormones operate in part by modulating protein translation [23, 24, 40, 75]. Translational regulation is slowly coming of age as a mechanism for regulating foreign gene expression in plants, beginning with translational enhancers [84, 85] and more recently, coordinating the expression of multiple transgenes using internal ribosome entry sites. Our contribution to understanding the molecular mode of action of a protein complex as fundamental as eIF3 is likely to lead to advances that will be applicable in the foreseeable future.
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Zimmerman, Ephraim, and Staphanie Perles. Vegetation monitoring in relation to white-tailed deer browsing in First State National Historical Park: 2021 summary report. National Park Service, 2023. http://dx.doi.org/10.36967/2299655.
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Baseline information on canopy regeneration and plant community composition is needed in order to better understand white-tailed deer browsing impacts at First State National Historical Park (FRST). In 2021, the Pennsylvania Natural Heritage Program (PNHP) established 20 permanent vegetation monitoring plots following methods developed by the NPS Eastern Rivers and Mountains Network (ERMN) to assess and monitor trends in vegetation (Perles et al. 2014b; Perles et al. 2017). These protocols provided an efficient method of assessing the current status of native and non-native vegetation and deer browsing impact. This report documents the methodology used to quantify the vegetative composition of natural areas at FRST and provides a summary of the data collected in the first year of monitoring. This first year’s activities (2021) included the initial baseline vegetation assessment and summary of results from the baseline data analysis. A variety of metrics used to assess the impact of deer browsing on the vegetation were calculated and are presented. A second survey is proposed for 2024. PNHP used the NPS ERMN database and analysis methods (Perles et al. 2014b) to summarize the condition in year 1 (2021). In year 4 (2024), PNHP will investigate changes in the condition of browse-sensitive understory plants and tree seedlings. Plots occurred in a variety of settings, ranging from younger successional communities to more mature forest stands. Seventy-five percent (75%) of the plots occurred in Mature or Late Successional forests. Disturbances and stressors, such as deer browsing can strongly influence future forest structure as open woodlands mature. A large population of white-tailed deer may severely impact succession from the open woodlands towards closed canopy forest. In closed canopy, later successional forests, a large deer population may inhibit canopy tree recruitment leading to regeneration failure. Given that FRST managers desire to maintain the landscape as forest, it is important to maintain an adequate number of seedlings and saplings of tree species to ensure the persistence of canopy of native tree species as Mature and Late Successional Forests continue to age. The 20 permanent sampling plots occurred within 5 plant communities described by Ebert (2016) and were classified using agglomerative hierarchical clustering (HAC analysis) and indicator species analysis. The most common plant communities within the group of sampling plots were the Mixed oak – beech forest and Mesic mixed tulip – oak-hickory-beech forest. The remaining plots were found in successional Tuliptree woodland, Successional woodland, and Thicket types. All plots were assigned to these types described in Ebert (2016) and crosswalked to the National Vegetation Classification (USNVC). A total of 128 plant species were recorded from the 20 plots at FRST. Eighteen (18) species were found in over ½ of the plots surveyed, of which eight (8) were non-native. In all, 29 plants occurring in the plots (23% of total species richness) were considered introduced (non-native). Non-native plant cover ranged from 0–98% as measured in the monitoring plot quadrats. Indicators of deer browsing varied by plant community type at FRST. In general, the drier Mixed oak – beech forests showed substantially greater impact of deer browsing and fewer seedlings of canopy species in the understory. FRST monitoring protocols focus on a few plant species considered as preferred food for white-tailed deer. Sustained browsing may be affecting long-term viability of these species within the parks. Based on the status of these regeneration metrics in FRST, we suggest that the forest in FRST are in imminent regeneration failure. We define imminent failure as parks that are experiencing severe regeneration failure and are at risk of forest loss due to very low seedling and sapling abundance, as well as species mismatches between canopy and regeneration layers. Given the poor regeneration of canopy species across all community types at FRST, managers should seek opportunities to conduct adaptive management in the park’s forests, especially mixed oak – beech forest, to experiment with and monitor the effects of fire, browse exclosures, and canopy thinning to encourage native canopy tree regeneration.
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Ward, Kimiora. Sierra Nevada Network high elevation white pine monitoring: 2021 annual report. National Park Service, 2024. http://dx.doi.org/10.36967/2302327.
Full textAbstract:
Five-needle white pines (Family Pinaceae, Genus Pinus, Subgenus Strobus), and in particular whitebark pine (Pinus albicaulis), limber pine (P. flexilis), and foxtail pine (P. balfouriana) are foundation species in upper subalpine and treeline forests of several National Park Service Pacific West Region parks, including Sequoia and Kings Canyon National Parks (SEKI) and Yosemite National Park (YOSE). The Sierra Nevada Network Inventory & Monitoring Program, in collaboration with the Klamath Network, Upper Columbia Basin Network, and Mojave Desert Network have implemented a joint long-term monitoring protocol to assess the current status and future trends in high elevation white pine communities. Key demographic parameters within white pine forest communities will be estimated by monitoring individual trees within permanent plots through time. This report documents the results of the 2021 field season, which was the eighth year of monitoring in Sequoia and Kings Canyon National Parks (SEKI) and Yosemite National Park (YOSE). The 2021 goal was to complete the third full re-measure of the second of three rotating panels (Panel 2) for each species-park population: YOSE-whitebark pine, SEKI-whitebark pine, and SEKI-foxtail pine. Each panel consists of 12 permanent 50 x 50 m (2,500 m2) plots that were randomly selected for each of the three populations. The full sampling array thus includes a total of 36 whitebark pine plots in YOSE, 36 whitebark pine plots in SEKI, and 36 foxtail pine plots in SEKI. Data from plot surveys will be used to characterize white pine forest community dynamics in SEKI and YOSE, including changes in tree species composition, forest structure, forest health, and demographics. The first full measure of all Panel 2 plots was completed over two years in 2013-2014, then a full remeasure of both parks? whitebark pine Panel 2 was conducted in 2016, with 10 of 12 SEKI-foxtail plots sampled that year. A third remeasure of all Panel 2 plots was not possible in 2021 because a smaller crew size was necessary during the COVID-19 pandemic. In total, the crew visited 37 sites, and sampled 31, during the 2021 field season. One plot in the YOSE whitebark pine frame was uninstalled before reading and one plot in the SEKI whitebark pine frame was uninstalled after reading, both for safety concerns. Four plots were not visited due to lack of capacity with the reduced crew size: one in each of the YOSE and SEKI whitebark frames, and three in the SEKI foxtail frame. A plot from Panel 3 in each of the parks? whitebark frames was measured, for a total of 11 plots measured in each whitebark pine frame. Nine plots were measured in the SEKI foxtail pine frame. Within the 31 plots completed, a total of 5,728 trees was measured. Species composition, forest structure, and factors affecting tree health and reproduction, including incidence and severity of white pine blister rust (Cronartium ribicola) infection, mountain pine beetle (Dendroctonus ponderosae) infestation, dwarf mistletoe (Arceuthobium spp.) infection, canopy kill, female cone production and regeneration were recorded. During the 2021 field season, crews continued to count the total number of mature cones per tree for whitebark and foxtail pine, use crown condition codes to assess crown health, and tag individual seedlings to be tracked through time. All three of these procedures started in 2017 and are to be evaluated by each of the three participating networks over several years, to determine whether they should become permanent changes to the monitoring protocol. In YOSE, 11 whitebark pine plots were re-measured, from Panels 2 and 3. A total of 2,810 trees were sampled, which included 586 live whitebark pine trees and 2,097 other live conifers. An additional 127 trees (including 17 whitebark pine) were recorded as dead. The forest crew noted little sign of white pine blister rust (WPBR) in Yosemite in 2021, and just a single inactive canker was observed on one whitebark pine in Panel 3, Plot 42, near Dana Meadows. This infection was new to plot 42, and it expands the total number of plots where white pine blister rust has been documented in Yosemite to six. The crew also noted little mountain pine beetle activity, documenting beetle galleries on 15 lodgepole pines in three Panel 2 plots. Dwarf mistletoe was not observed. The average number of live whitebark pine trees per plot was 53 (SD = 56). This was a low cone crop year for whitebark pine, with two percent of live whitebark pine trees producing female cones. Cone bearing trees averaged 2 (SD = 1) cones per tree. Whitebark pine seedling density averaged 90 (SD = 157) seedlings per hectare. The largest number of whitebark pine seedlings found in a plot was four, and three of the eleven plots contained whitebark seedlings. In SEKI, 10 of 12 Panel 2, and one Panel 3, whitebark pine plots were re-measured. Within these plots, 1,246 live whitebark pine, 30 live foxtail pine, and 861 other live conifers were sampled. WPBR was infrequently documented in the SEKI whitebark frame as well, with indicators of infection in Plot 31 near Window Creek and Plot 44 near Upper State Lake. These were the first infections documented in these plots, bringing the number of plots where WPBR has been documented in the SEKI whitebark panel to nine. Although WPBR was documented in Plot 27 near Charlotte Dome in 2016, it was not documented this year because putative cankers showing three signs of infection in 2016 showed only two or fewer signs in 2021. Mountain pine beetle activity was observed in one live lodgepole pine and two recently dead whitebark pine, within three plots in the SEKI whitebark sample frame. An exception to the low levels of mountain pine beetle activity was outside Plot 31 in the Window Creek area, where the forest crew noted many recently dead whitebark pine with signs of beetle activity. Dwarf mistletoe was not encountered. The average number of live whitebark pine trees per plot was 113 (SD = 86). Less than one percent of live whitebark pine trees produced female cones, each producing on average 2 (SD = 1) cones. Whitebark seedling regeneration averaged 303 (SD = 319) seedlings per hectare. The largest number of whitebark seedlings found in a plot was eight, and eight of the 11 plots contained whitebark seedlings. Nine of the 12 SEKI foxtail Panel 3 plots were remeasured. Within these plots, 413 live foxtail pine, 67 live whitebark pine, and 402 other live conifers were sampled. Ninety-two dead or recently dead trees were also documented, 65 of which were foxtail pine. No signs of blister rust infection, mistletoe, or mountain pine beetle were observed in the foxtail plots sampled. The average number of foxtail pine trees per plot was 46 (SD = 33). Fifty-four percent of the foxtail pine trees produced female cones, averaging 14 (SD =15) cones/tree. Only one foxtail pine seedling was recorded within the 9 foxtail pine plots, resulting in an estimated 14 (SD = 41) seedlings per hectare. Eight whitebark pine seedlings were also found within two plots.
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Ward, Kimiora. Sierra Nevada Network white pine monitoring: 2022 annual report. National Park Service, 2023. http://dx.doi.org/10.36967/2301003.
Full textAbstract:
Five-needle white pines (Family Pinaceae, Genus Pinus, Subgenus Strobus), and in particular whitebark pine (Pinus albicaulis), limber pine (P. flexilis), and foxtail pine (P. balfouriana) are foundation species in upper subalpine and treeline forests of several National Park Service Pacific West Region parks, including Sequoia and Kings Canyon National Parks (SEKI) and Yosemite National Park (YOSE). The Sierra Nevada Network Inventory & Monitoring Program, in collaboration with the Klamath Network, Upper Columbia Basin Network, and Mojave Desert Network have implemented a joint long-term monitoring protocol to assess the current status and future trends in high elevation white pine communities. Key demographic parameters within white pine forest communities will be estimated by monitoring individual trees within permanent plots through time. This report documents the results of the 2022 field season, which was the ninth year of monitoring in SEKI and YOSE. The 2021 goal was to complete the first full measure of the third of three rotating panels (Panel 3) for each species-park population: YOSE-whitebark pine, SEKI-whitebark pine, and SEKI-foxtail pine. Each panel consists of 12 permanent 50 x 50 m (2,500 m2) plots that were randomly selected for each of the three populations. The full sampling array thus includes a total of 36 whitebark pine plots in YOSE, 36 whitebark pine plots in SEKI, and 36 foxtail pine plots in SEKI. Data from plot surveys will be used to characterize white pine forest community dynamics in SEKI and YOSE, including changes in tree species composition, forest structure, forest health, and demographics. Partial measures of Panel 3 were completed in 2017 (11 plots) in Yosemite whitebark pine, in 2017 (9 plots) in SEKI whitebark pine, and in 2014 (7 plots) and 2017-2018 (8, 1 plots) in foxtail pine. In 2022, the first full measure of all Panel 3 plots (and 2nd or 3rd remeasure of most plots) was successfully completed, and installation was completed on four of these plots in SEKI whitebark pine and two in foxtail pine. In total, the crew visited 36 sites during the 2022 field season, all from Panel 3. Within the 36 completed Panel 1 plots, a total of 6,398 trees were measured. Species composition, forest structure, and factors affecting tree health and reproduction including incidence and severity of white pine blister rust (Cronartium ribicola) infection, mountain pine beetle (Dendroctonus ponderosae) infestation, dwarf mistletoe (Arceuthobium spp.) infection, canopy kill, and female cone production were recorded. During the 2022 field season crews continued to count the total number of mature cones per tree for whitebark and foxtail pine, use crown condition codes to assess crown health, and tag individual seedlings to be tracked through time. All three of these procedures started in 2017 and are to be evaluated by each of the three participating networks over several years, to determine whether they should become permanent changes to the monitoring protocol. In YOSE, all 12 Panel 3 whitebark pine plots were measured. A total of 2,720 trees were sampled, which included 977 live whitebark pine trees and 1,605 other live conifers. An additional 135 trees (including 26 whitebark) were recorded as dead. The average number of live whitebark pine trees per plot was 81 (SD = 94). White pine blister rust (WPBR) aecia were observed on five whitebark pine in one plot in YOSE in 2022, and no trees in any plot had inactive cankers showing three or more indicators of WPBR. WPBR had previously been documented in this plot, so the number of plots where rust has ever been observed in Yosemite remains unchanged at six. However, an infection documented in plot 42 in 2021 was not observed again when the plot was resampled in 2022, so it is possible this number should be five. Mountain pine beetle activity was observed on one live whitebark pine and three live and one dead lodgepole pine in YOSE in 2022. Despite documentation of many stands impacted by beetle attack in the field crew notes, the quantified rate of MPB attack was lower than in 2021. Twenty-one percent of live whitebark pine trees produced female cones. Cone-bearing trees averaged 7 (SD = 10) cones/tree. Whitebark pine seedling density averaged 80 (SD = 152) seedlings per hectare. The largest number of whitebark pine seedlings found in a plot was 51 and five of the twelve plots contained whitebark seedlings. All 12 Panel 3 SEKI whitebark pine plots were measured in 2022, and installation was completed on four of these, so this Panel is now fully installed. Within these plots, 2,179 live whitebark pine, 10 live foxtail pine, and 297 other live conifers were sampled (including 5 live western white pine). The average number of live whitebark pine trees per plot was 181 (SD = 125). Although the crew observed white pine blister rust in seven SEKI whitebark Panel 3 plots, no active cankers (aecia) were observed, and no trees displayed 3 of 5 indicators, so no infections were quantified. Mountain pine beetle activity was observed in 18 live and 23 dead whitebark pine and 1 live and one dead lodgepole pine within three plots in SEKI. Dwarf mistletoe was not encountered. Seven percent of live whitebark pine trees produced female cones. Cone-bearing trees averaged 3.7 (SD = 3.6) cones/tree. Whitebark seedling regeneration averaged 700 (SD = 752) seedlings per hectare. The largest number of whitebark seedlings found in a plot was 19, and two of the 12 plots did not contain any whitebark seedlings. In the foxtail pine Panel 3, all 12 plots were measured in 2022, and installation was completed on two of these, so installation of the panel is now complete. Within these plots we measured 309 live foxtail pine, 302 live whitebark pine, and 380 other live conifers, including four live western white pine. An additional 112 dead or recently dead trees and 22 unidentified snags were also measured, 19 of which were foxtail pine. The average number of foxtail pine trees per plot was 26 (SD = 26). No signs of blister rust infection or mistletoe were observed on foxtail pine. Mountain pine beetle activity was observed on one dead foxtail pine, one live whitebark pine, and seven live and one dead lodgepole pines within four plots. Sixty-two percent of the foxtail pine trees produced female cones. Cone-bearing trees averaged 33 (SD = 53) cones/tree. Seven foxtail pine seedlings were recorded within five plots, resulting in an estimated 72 (SD = 98) seedlings per hectare. Eight whitebark pine seedlings and three lodgepole pine seedlings were also found within three additional plots.
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Livensperger, Carolyn, Rebecca Weissinger, Luke Gommermann, and Alice Wondrak Biel. Riparian monitoring of wadeable streams on the Fremont River, Capitol Reef National Park, 2009?2021. National Park Service, 2023. http://dx.doi.org/10.36967/2301391.
Full textAbstract:
The goal of Northern Colorado Plateau Network (NCPN) riparian monitoring is to deter-mine long-term trends in hydrologic, geomorphic, and vegetative properties of wadeable streams in the context of changes in other ecological drivers, stressors, and processes. This information is intended to provide early warning of resource degradation and determine natural variability of wadeable streams. This report summarizes NCPN monitoring of the Fremont River in Capitol Reef National Park (NP) from water years 2009 to 2021. The focus of this report is to (1) examine patterns in water availability at one monitoring reach from 2010 to 2021, and (2) present geomorphology and vegetation data from four reaches monitored from 2009 to 2021. Vegetation sampling and geomorphology surveys were completed at varying intervals throughout the time period; this report looks at changes within single reaches and establishes a baseline for future comparisons. There are four monitoring reaches established on the Fremont River: (1) F-01, approximately 2.5 kilometers upstream of a knickpoint (sharp change in channel slope) and associated waterfall that emerged following construction of State Highway 24 in 1964, (2) F-07, in a large oxbow that was cut off due to the highway construction, (3) F-04, approximately 1.5 kilometers downstream of the knickpoint, and (4) F-14, approximately 4.8 kilometers downstream of the knickpoint. Geomorphic and vegetation surveys took place at all reaches. Hydrologic monitoring occurred only at F-01. From 2001 to 2021, the entire range of flows recorded at a gaging station on the Fremont River upstream of the park near Bicknell, Utah, decreased, with the steepest decreases occurring in the highest flow percentiles. Continuous hydrologic monitoring at reach F-01 in the park from 2010 to 2021 showed perennial flows in the Fremont River, with lower flows during the irrigation season (April 1?October 31). The irrigation season was also characterized by greater evapotranspiration, which may be exacerbated in the future due to higher air temperatures. Lower observed inputs and greater evapotranspiration suggest the Fremont River is at risk for progressively lower flows over time. While overbank flows occurred infrequently in the monitoring reach, inhibiting cottonwood recruitment, groundwater levels remained shallow enough to support mature cottonwood trees. Protecting spring snowmelt flows of 94 cfs (the average annual maximum 14-day rolling mean at reach F-01), or greater should maintain the current wetland vegetated zone. Maintaining the hydrologic record was challenging due to high-magnitude flood events and turbid flows; the park should consider a gaging station for an accurate discharge record. Geomorphic surveys showed net sediment deposition at reaches F-01 and F-14 in the channels, banks, and floodplains from 2009 to 2021, with more deposition occurring earlier in the study period. A large flood event in 2013 resulted in high flows and deposition of close to one meter at F-01. Only localized erosion occurred, and thalweg surveys showed that stream channels were either stable or increasing in elevation. Reach F-07, the abandoned oxbow, exhibited little geomorphic change over the study period. Riparian vegetation was characteristic of a Fremont cottonwood woodland, with canopy closure up to 30% and a mixed understory of shrubs and herbaceous species. Obligate wetland vegetation cover of 5%?10% was present at reaches F-01, F-04, and F-14. Reach F-07, in the oxbow, has transitioned to an upland system, with little to no canopy cover and no obligate wetland species. While mature cottonwoods were present in reaches F-01, F-04, and F-14, there was limited evidence of seedlings or saplings graduating into larger size classes. Cottonwood seedlings are primarily resprouts from beaver-browsed trees, although one seedling recruitment event was observed in 2014, following high flows in late 2013. Protecting some cottonwoods with chicken wire may help protect the larger size classes and maintain a mixed-age woodland. Exotic plant species cover was less than 10% in reaches F-01, F-04, and F-14. Efforts to control Russian olive (Eleagnus angustifolia) along the Fremont River appear to have been successful in these reaches. In reach F-07, exotic plant cover ranged from 9% to 25%, with notable spikes in Russian thistle (Salsola tragus) and cheatgrass (Bromus tectorum) in 2010 and 2011, respectively.
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Sela, Hanan, Eduard Akhunov, and Brian J. Steffenson. Population genomics, linkage disequilibrium and association mapping of stripe rust resistance genes in wild emmer wheat, Triticum turgidum ssp. dicoccoides. United States Department of Agriculture, 2014. http://dx.doi.org/10.32747/2014.7598170.bard.
Full textAbstract:
The primary goals of this project were: (1) development of a genetically characterized association panel of wild emmer for high resolution analysis of the genetic basis of complex traits; (2) characterization and mapping of genes and QTL for seedling and adult plant resistance to stripe rust in wild emmer populations; (3) characterization of LD patterns along wild emmer chromosomes; (4) elucidation of the multi-locus genetic structure of wild emmer populations and its correlation with geo-climatic variables at the collection sites. Introduction In recent years, Stripe (yellow) rust (Yr) caused by Pucciniastriiformis f. sp. tritici(PST) has become a major threat to wheat crops in many parts of the world. New races have overcome most of the known resistances. It is essential, therefore, that the search for new genes will continue, followed by their mapping by molecular markers and introgression into the elite varieties by marker-assisted selection (MAS). The reservoir of genes for disease and pest resistance in wild emmer wheat (Triticumdicoccoides) is an important resource that must be made available to wheat breeders. The majority of resistance genes that were introgressed so far in cultivated wheat are resistance (R) genes. These genes, though confering near-immunity from the seedling stage, are often overcome by the pathogen in a short period after being deployed over vast production areas. On the other hand, adult-plant resistance (APR) is usually more durable since it is, in many cases, polygenic and confers partial resistance that may put less selective pressure on the pathogen. In this project, we have screened a collection of 480 wild emmer accessions originating from Israel for APR and seedling resistance to PST. Seedling resistance was tested against one Israeli and 3 North American PST isolates. APR was tested on accessions that did not have seedling resistance. The APR screen was conducted in two fields in Israel and in one field in the USA over 3 years for a total of 11 replicates. We have found about 20 accessions that have moderate stripe rust APR with infection type (IT<5), and about 20 additional accessions that have novel seedling resistance (IT<3). We have genotyped the collection using genotyping by sequencing (GBS) and the 90K SNP chip array. GBS yielded a total 341K SNP that were filtered to 150K informative SNP. The 90K assay resulted in 11K informative SNP. We have conducted a genome-wide association scan (GWAS) and found one significant locus on 6BL ( -log p >5). Two novel loci were found for seedling resistance. Further investigation of the 6BL locus and the effect of Yr36 showed that the 6BL locus and the Yr36 have additive effect and that the presence of favorable alleles of both loci results in reduction of 2 grades in the IT score. To identify alleles conferring adaption to extreme climatic conditions, we have associated the patterns of genomic variation in wild emmer with historic climate data from the accessions’ collection sites. The analysis of population stratification revealed four genetically distinct groups of wild emmer accessions coinciding with their geographic distribution. Partitioning of genomic variance showed that geographic location and climate together explain 43% of SNPs among emmer accessions with 19% of SNPs affected by climatic factors. The top three bioclimatic factors driving SNP distribution were temperature seasonality, precipitation seasonality, and isothermality. Association mapping approaches revealed 57 SNPs associated with these bio-climatic variables. Out of 21 unique genomic regions controlling heading date variation, 10 (~50%) overlapped with SNPs showing significant association with at least one of the three bioclimatic variables. This result suggests that a substantial part of the genomic variation associated with local adaptation in wild emmer is driven by selection acting on loci regulating flowering. Conclusions: Wild emmer can serve as a good source for novel APR and seedling R genes for stripe rust resistance. APR for stripe rust is a complex trait conferred by several loci that may have an additive effect. GWAS is feasible in the wild emmer population, however, its detection power is limited. A panel of wild emmer tagged with more than 150K SNP is available for further GWAS of important traits. The insights gained by the bioclimatic-gentic associations should be taken into consideration when planning conservation strategies.
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Seginer, Ido, Daniel H. Willits, Michael Raviv, and Mary M. Peet. Transpirational Cooling of Greenhouse Crops. United States Department of Agriculture, 2000. http://dx.doi.org/10.32747/2000.7573072.bard.
Full textAbstract:
Background Transplanting vegetable seedlings to final spacing in the greenhouse is common practice. At the time of transplanting, the transpiring leaf area is a small fraction of the ground area and its cooling effect is rather limited. A preliminary modeling study suggested that if water supply from root to canopy is not limiting, a sparse crop could maintain about the same canopy temperature as a mature crop, at the expense of a considerably higher transpiration flux per leaf (and root) area. The objectives of this project were (1) to test the predictions of the model, (2) to select suitable cooling methods, and (3) to compare the drought resistance of differently prepared seedlings. Procedure Plants were grown in several configurations in high heat load environments, which were moderated by various environmental control methods. The difference between the three experimental locations was mainly in terms of scale, age of plants, and environmental control. Young potted plants were tested for a few days in small growth chambers at Technion and Newe Ya'ar. At NCSU, tomato plants of different ages and planting densities were compared over a whole growing season under conditions similar to commercial greenhouses. Results Effect of spacing: Densely spaced plants transpired less per plant and more per unit ground area than sparsely spaced plants. The canopy temperature of the densely spaced plants was lower. Air temperature was lower and humidity higher in the compartments with the densely spaced plants. The difference between species is mainly in the canopy-to-air Bowen ratio, which is positive for pepper and negative for tomato. Effect of cooling methods: Ventilation and evaporative pad cooling were found to be effective and synergitic. Air mixing turned out to be very ineffective, indicating that the canopy-to-air transfer coefficient is not the limiting factor in the ventilation process. Shading and misting, both affecting the leaf temperature directly, proved to be very effective canopy cooling methods. However, in view of their side effects, they should only be considered as emergency measures. On-line measures of stress: Chlorophyll fluorescence was shown to accurately predict photosynthesis. This is potentially useful as a rapid, non-contact way of assessing canopy heat stress. Normalized canopy temperature and transpiration rate were shown to correlate with water stress. Drought resistance of seedlings: Comparison between normal seedlings and partially defoliated ones, all subjected to prolonged drought, indicated that removing about half of the lowermost leaves prior to transplanting, may facilitate adjustment to the more stressful conditions in the greenhouse. Implications The results of this experimental study may lead to: (1) An improved model for a sparse canopy in a greenhouse. (2) A better ventilation design procedure utilizing improved estimates of the evaporation coefficient for different species and plant configurations. (3) A test for the stress resistance of transplants.
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Flaishman, Moshe, Herb Aldwinckle, Shulamit Manulis, and Mickael Malnoy. Efficient screening of antibacterial genes by juvenile phase free technology for developing resistance to fire blight in pear and apple trees. United States Department of Agriculture, 2008. http://dx.doi.org/10.32747/2008.7613881.bard.
Full textAbstract:
Objectives: The original objectives of this project were to: Produce juvenile-free pear and apple plants and examine their sensitivity to E. amylovora; Design novel vectors, for antibacterial proteins and promoters expression, combined with the antisense TFL1 gene, and transformation of Spadona pear in Israel and Galaxy apple in USA. The original objectives were revised from the development of novel vectors with antibacterial proteins combined with the TFL-1 due to the inefficiency of alternative markes initially evaluated in pear, phoshomannose-isomerase and 2-deoxyglucose-6-phosphate phosphatase and the lack of development of double selection system. The objectives of project were revised to focus primarily on the development additional juvenile free systems by the use of another pear variety and manipulation of the FT gene under the control of several promoters. Based on the results creation of fire blight resistance pear variety was developed by the use of the juvenile free transgenic plant. Background: Young tree seedlings are unable to initiate reproductive organs and require a long period of shoot maturation, known as juvenile phase. In pear, juvenile period can last 5-7 years and it causes a major delay in breeding programs. We isolated the TFL1 gene from Spadona pear (PcTFL1-1) and produced transgenic ‘Spadona’ trees silencing the PcTFL1 gene using a RNAi approach. Transgenic tissue culture ‘Spadona’ pear flowered in vitro. As expected, the expression of the endogenous PcTFL1 was suppressed in the transgenic line that showed precocious flowering. Transgenic plants were successfully rooted in the greenhouse and most of the plants flowered after only 4-8 months, whereas the non-transformed control plants have flowered only after 5-6 years of development. Major achievements: Prior to flower induction, transgenic TFL1-RNAi ‘Spadona’ plants developed a few branches and leaves. Flower production in the small trees suppressed the development of the vegetative branches, thus resulting in compact flowering trees. Flowering was initiated in terminal buds, as described for the Arabidopsis tfl1 mutant. Propagation of the transgenic TFL1-RNAi ‘Spadona’ was performed by bud grafting on 'Betulifolia' rootstock and resulted in compact flowering trees. The transgenic flowering grafted plants were grown in the greenhouse under a long photoperiod for one year, and flowered continuously. Pollination of the transgenic flowers with ‘Costia‘ pear pollen generated fruits of regular shape with fertile F1 seeds. The F1 transgenic seedling grown in the greenhouse formed shoots and produced terminal flowers only five months after germination. In addition, grafted F1 transgenic buds flower and fruit continuously, generating hybrid fruits with regular shape, color and taste. Several pear varieties were pollinated with the transgenic TFL1-RNAi ‘Spadona’ pollen including `Herald Harw` that was reported to have resistance to fire blight diseases. The F-1 hybrid seedlings currently grow in our greenhouse. We conclude that the juvenile-free transgenic ‘Spadona’ pear enables the development of a fast breeding method in pear that will enable us to generate a resistance pear to fire blight. Implications: The research supported by this grant has demonstrated the use of transgenic juvenile free technology in pear. The use of the juvenile free technology for enhancement of conventional breeding in fruit tree will serve to enhance fast breeding systems in pear and another fruit trees.
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Yu, Zhang, Fu Yao, Yang Xuefei, et al. Vegetables from local markets in Myanmar. International Centre for Integrated Mountain Development (ICIMOD), 2022. http://dx.doi.org/10.53055/icimod.1011.
Full textAbstract:
This book enumerates the diversity in the prevalence and use of vegetables in parts of Myanmar. It draws on our field studies in Myanmar, where we encountered people consuming interesting plant species as vegetables. For example, we saw parts of the moorva dregea (Wattakaka volubilis), belonging to the family Apocyanaceae, and jengkol (Archidendron pauciflorum), belonging to the family Fabaceae, being consumed as vegetables. These plants are generally considered poisonous by scientists. Likewise, the roots of the winged bean (Psophocarpus tetragonolobus) and the seedlings of the wine palm (Borassus flabellifer), which have a pungent taste, are very popular vegetables in the dry season in Myanmar. Tea is a globally well-known and widely-consumed beverage. However, in Myanmar, Pu’er tea (Camellia sinensis var. assamica) is consumed as a beverage and a vegetable. The leaf that is consumed as a vegetable is fermented and preserved.