Academic literature on the topic 'Seedling Tolerance'

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Journal articles on the topic "Seedling Tolerance"

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Cobb, B. G., D. L. Andrews, D. M. MacAlpine, J. R. Johnson, and M. C. Drew. "1001 ANOXIA TOLERANCE OF MAIZE SEEDLING ROOTS." HortScience 29, no. 5 (1994): 573a—573. http://dx.doi.org/10.21273/hortsci.29.5.573a.

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We have been examining the response of maize seedling roots to oxygen stress. Previously, we have shown that maize seedlings with primary root lengths of 10cm or greater require a pretreatment with low oxygen (hypoxia) for survival of greater than 12 hours of anoxia. During the pretreatment there is induction of mRNA and increase in enzymatic activity of alcohol dehydrogenase (ADH) and other enzymes that are necessary for alcoholic fermentation. However, we have found that younger seedlings do not need a pretreatment to survive anoxia. They appear to have high levels of ADH and other enzymes that are needed for anaerobic survival at levels equivalent to those that are induced in older seedlings. These results suggest that, at the time of seedling emergence, seedlings may be more adapted to oxygen stress than during later stages of growth.
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Xu, Yunji, Xuelian Weng, Liqiu Jiang, et al. "Screening and Evaluation of Salt-Tolerant Wheat Germplasm Based on the Main Morphological Indices at the Germination and Seedling Stages." Plants 13, no. 22 (2024): 3201. http://dx.doi.org/10.3390/plants13223201.

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The successful screening and evaluation of salt-tolerant germplasm at the germination and seedling stages is of great importance for promoting the breeding of wheat varieties with salt tolerance. In this study, 70 wheat varieties bred in different regions were evaluated for salt tolerance through hydroponic exposure to different concentrations of salt. The relative water absorption, water absorption rate, dehiscence rate, germination rate, and germination index of seeds, and plant height, root length, stem diameter, and biomass of seedlings were determined at the germination and seedling stages of wheat, and the salt tolerance was identified and evaluated using multivariate statistical analysis. The germination ability and seedling growth potential of wheat germplasms decreased with the aggravation of salt stress. Based on the comprehensive salt tolerance index at the germination stage, our study identified 35 varieties to be salt-tolerant. There were nine varieties further screened for having strong salt tolerance according to the comprehensive salt tolerance index at the germination and seedling stages. SN41, Emam, YN301, and JM262 were superior in salt-tolerance, and YM39, LM30, JM60, YN999, and SD29 were salt-tolerant. Our study suggests that the biomass of seedlings can be used as a key parameter for assessing wheat germplasm’s ability to withstand salt. Our results can provide some basic materials for cultivating new germplasm with salt tolerance and excavating the related genes of wheat.
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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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Ye, Nenghui, Yuxing Wang, Huihui Yu, et al. "Abscisic Acid Enhances Trehalose Content via OsTPP3 to Improve Salt Tolerance in Rice Seedlings." Plants 12, no. 14 (2023): 2665. http://dx.doi.org/10.3390/plants12142665.

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Salt stress is one of the major environmental stresses that imposes constraints to plant growth and production. Abscisic acid (ABA) has been well-proven to function as a central integrator in plant under salt stress, and trehalose (Tre) has emerged as an excellent osmolyte to induce salt tolerance. However, the interacting mechanism between ABA and Tre in rice seedlings under salt stress is still obscure. Here, we found that the application of exogenous Tre significantly promoted the salt tolerance of rice seedlings by enhancing the activities of antioxidant enzymes. In addition, the expression of OsNCED3 was significantly induced by salt stress. The overexpression of the OsNCED3 gene enhanced the salt tolerance, while the knockout of OsNCED3 reduced the salt tolerance of the rice seedlings. Metabolite analysis revealed that the Tre content was increased in the OsNCED3-overexpressing seedlings and reduced in the nced3 mutant. The application of both ABA and Tre improved the salt tolerance of the nced3 mutant when compared with the WT seedling. OsTPP3 was found to be induced by both the ABA and salt treatments. Consistent with the OsNCED3 gene, the overexpression of OsTPP3 enhanced salt tolerance while the knockout of OsTPP3 reduced the salt tolerance of the rice seedlings. In addition, the Tre content was also higher in the OsTPP3-overexpressing seedling and lower in the tpp3 mutant seedling than the WT plant. The application of exogenous Tre also enhanced the salt tolerance of the tpp3 mutant plant. Overall, our results demonstrate that salt-increased ABA activated the expression of OsTPP3, which resulted in elevated Tre content and thus an improvement in the salt tolerance of rice seedlings.
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Zhang, Xijuan, Kai Liu, Chuanming Yang, et al. "Detection of Quantitative Trait Loci Associated with Alkaline Tolerance Using Recombinant Inbred Line Population Derived from Longdao5 × Zhongyouzao8 at Seedling Stage." Life 14, no. 9 (2024): 1151. http://dx.doi.org/10.3390/life14091151.

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Salt–alkaline stress is one of the most stressful occurrences, causing negative effects on plant development and agricultural yield. Identifying and utilizing genes that affect alkaline tolerance is an excellent approach to accelerate breeding processes and meet the needs for remediating saline–alkaline soil. Here, we employed a mapping population of 176 recombinant inbred lines (RILs) produced from a cross between alkali-tolerant Longdao5 and alkali-sensitive Zhongyouzao8 to identify the quantitative trait loci (QTLs) determining alkali tolerance at the seedling stage. For the evaluation of alkali tolerance, the recovered seedling’s average alkali tolerance index (ATI), root number (RN), root length (RL), seedling dry weight (SW), root dry weight (RW), and seedling height (SH) were assessed, together with their relative alkaline damage rate. Under alkaline stress, the ATI was substantially negative connected with the root number, seedling height, seedling dry weight, and root dry weight; however, it was considerably positive correlated with the relative alkaline damage rate of the root number and root dry weight. A total of 13 QTLs for the root number, root length, seedling height, seedling dry weight, root dry weight, and alkali tolerance index under alkaline stress were identified, which were distributed across chromosomes 1, 2, 3, 4, 5, 7, and 8. All of these QTLs formed two QTL clusters for alkali tolerance on chromosome 5 and chromosome 7, designated AT5 and AT7, respectively. Nine QTLs were identified for the relative alkaline damage rate of the root number, root length, seedling height, seedling dry weight, and root dry weight under alkali stress. These QTLs were located on chromosome 2, 4, 6, 7, 8, 9, and 12. In conclusion, these findings further strengthen our knowledge about rice’s genetic mechanisms for alkaline tolerance. This research offers clues to accelerate breeding programs for new alkaline-tolerance rice varieties.
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Noland, Thomas L., Rongzhou Man, and Michael Irvine. "Glyphosate tolerance of eastern white cedar: Third year results." Forestry Chronicle 93, no. 02 (2017): 190–93. http://dx.doi.org/10.5558/tfc2017-025.

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Little is known about the herbicide tolerance of eastern white cedar (Thuja occidentalis L.). To determine the sensitivity of cedar seedlings to timing and concentration of herbicide applications, glyphosate was applied to 2-year-old seedlings at three concentrations (1.04, 2.07, and 4.14 acid equivalent (ae) kg ha-1) at three times (July 28, August 10 and 31), at a research site in north central Ontario. Seedling survival, growth, and biomass three years after spraying were compared with those of seedlings in manual weeding (competition/weed free via manual weeding) and control (no weeding and therefore always competition/weeds) treatments. Only glyphosate applied at 4.14 ae kg ha-1 significantly reduced, by 27%, third year seedling survival. Pattern of sensitivity of cedar seedling growth to glyphosate was diameter>height. Seedlings treated with 2.07 and 4.14 ae kg ha-1 glyphosate had significantly less root biomass than those in the control plots, whereas only cedar treated with 4.14 ae kg ha-1 glyphosate had lower shoot biomass. Application timing made no difference in survival, growth, or final biomass. All glyphosate and the no weeding control treatments reduced root, shoot, and total biomass of cedar relative to the manually weeded seedlings.
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Poggi, Giovanni Maria, Simona Corneti, and Iris Aloisi. "The Quest for Reliable Drought Stress Screening in Tetraploid Wheat (Triticum turgidum spp.) Seedlings: Why MDA Quantification after Treatment with 10% PEG-6000 Falls Short." Life 14, no. 4 (2024): 517. http://dx.doi.org/10.3390/life14040517.

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Drought stress poses significant productivity challenges to wheat. Several studies suggest that lower malondialdehyde (MDA) content may be a promising trait to identify drought-tolerant wheat genotypes. However, the optimal polyethylene glycol (PEG-6000) concentration for screening seedlings for drought tolerance based on MDA quantification is not clear. The aim of this study was to verify whether a 10% (w/v) PEG-6000 concentration-induced water stress was reliable for discriminating between twenty-two drought-susceptible and drought-tolerant tetraploid wheat (Triticum turgidum spp. durum, turanicum, and carthlicum) accessions based on MDA quantification. To do so, its correlation with morpho-physiological traits, notoriously related to seedling drought tolerance, i.e., Seedling Vigour Index and Seedling Water Content, was evaluated. Results showed that MDA content was not a reliable biomarker for drought tolerance, as it did not correlate significantly with the aforementioned morpho-physiological traits, which showed, on the contrary, high positive correlation with each other. Combining our study with the cited literature, it clearly emerges that different wheat genotypes have different “water stress thresholds”, highlighting that using a 10% PEG-6000 concentration for screening wheat seedlings for drought tolerance based on MDA quantification is not reliable. Given the conflicting results in the literature, this study provides important insights for selecting appropriate methods for evaluating wheat seedling drought tolerance.
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Subramanian, M., K. Ganesan, W. W. Manuel, and T. Sundaram. "Seedling Tolerance for Dehydrating Wind." International Rice Research Newsletter 12, no. 2 (1987): 22–23. https://doi.org/10.5281/zenodo.7122611.

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This article 'Seedling Tolerance for Dehydrating Wind' appeared in the International Rice Research Newsletter series, created by the International Rice Research Institute (IRRI). The primary objective of this publication was to expedite communication among scientists concerned with the development of improved technology for rice and for rice based cropping systems. This publication will report what scientists are doing to increase the production of rice in as much as this crop feeds the most densely populated and land scarce nations in the world.
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Kaminski, John E., Peter H. Dernoeden, and Cale A. Bigelow. "Creeping Bentgrass Seedling Tolerance to Herbicides and Paclobutrazol." HortScience 39, no. 5 (2004): 1126–29. http://dx.doi.org/10.21273/hortsci.39.5.1126.

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The tolerance of creeping bentgrass (Agrostis stolonifera L.) seedlings to many herbicides has not been evaluated. Three field studies were conducted between fall and spring from 1998 to 2002 to assess creeping bentgrass seedling tolerance to five herbicides and paclobutrazol. The primary objectives of this investigation were to assess bentgrass tolerance to these chemicals when applied at various timings following seedling emergence, and establishment of new seedlings as influenced by potential soil residues in the spring following a fall application of the chemicals. Treatments were applied 2, 4, or 7 weeks after either `Crenshaw' or `L-93' creeping bentgrass seedlings had emerged. Siduron (6.7 and 9.0 kg·ha-1) and bensulide (8.4 kg·ha-1) were noninjurious when applied two weeks after seedling emergence (2 WASE). Bensulide (14 kg·ha-1), ethofumesate (0.84 kg·ha-1), prodiamine (0.36 kg·ha-1) and paclobutrazol (0.14 kg·ha-1) were too injurious to apply 2 WASE, but they were generally safe to apply at 4 WASE. Chlorsulfuron (0.14 kg·ha-1) was extremely phytotoxic to seedlings when applied 2 WASE. Plots were treated with glyphosate and overseeded the following spring. The overwintering soil residuals of prodiamine and bensulide (14.0 kg·ha-1) unacceptably reduced spring establishment. All other herbicides and paclobutrazol had little or no adverse residual effects on spring establishment. Chemical names used: N-(phosphonomethyl)gycline (glyphosate); (±)-(R*,R*)-beta-[(4-chlorophenyl)methyl]-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol); 2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate (ethofumesate); S-(0,0-diisopropyl phosphorodithioate) ester of N-(2-mercaptoethyl) benzenesulfonamide (bensulide); [1-(2-methylcyclohexyl)-3-phenylurea] (siduron); N3,N3-di-n-propyl-2,4-dinitro-6-(trifluoromethyl)-m-phenylenediamine (prodiamine); 2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonyl] benzenesulfonamide (chlorsulfuron).
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Setyawan, Bayu, Niken Puspitasari, Agung Wahyu Susilo, and Indah Anita Sari. "Rootstock Characteristics of Three Combinations of Theobroma cacao L. Crosses on Different Water Availability." Pelita Perkebunan (a Coffee and Cocoa Research Journal) 34, no. 3 (2018): 137–45. http://dx.doi.org/10.22302/iccri.jur.pelitaperkebunan.v34i3.328.

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Climate change is universal phenomena which is importantly anticipated including cocoa plantation. Drought tolerance cocoa seedling is urgently neededto develop cocoa plantation. This paper studied possible drought tolerance of cocoa seedling through crossing between female parent KKM 22 with three maleparents BAL 209, KW 641, and KW 614. Progeny test was conducted in green house based on four water availability conditions: 25, 50, 75, and 100%. Root condition was recorded as rootstock parameters of three crossings. Result showed that root characteristics varied among crossing samples studied. The longestand hight volume root were recorded from KKM 22 x BAL 209 crossing. Seedling of KKM 22 x BAL 209 crossing tended to have long and wide root, while seedling of KKM 22 x KW 641 crossing tended to have a wide root type and seedling of KKM 22 x KW 614 tended to have a long root type. Based on drought tolerancy, seedling of KKM 22 x KW 641 crossing could be classified as drought tolerance while other two group progenies could be classified as susceptible to drought.To conclude, seedling of KKM 22 x KW 641 can be recommended for cocoa plantation in drought area.
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Dissertations / Theses on the topic "Seedling Tolerance"

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McKimmie, Tim, and Albert Dobrenz. "Salt Tolerance During Seedling Establishment in Alfalfa." College of Agriculture, University of Arizona (Tucson, AZ), 1987. http://hdl.handle.net/10150/203790.

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Deposition of salts from irrigation water is an increasing concern for Arizona farmers and agronomists. Selection for salt tolerance during the seedling stage has been undertaken over the past three years. Yield tests were conducted in greenhouses and a significant increase in dry matter production was shown in the selected material.
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Carter, Sara Katherine. "TOLERANCE OF SEEDLING TURFGRASS SPECIES TO ALS INHIBITING HERBICIDES." UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_theses/429.

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Acetolactate synthase (ALS) inhibiting herbicides are commonly used to eliminate weeds from mature turfgrasses. Field trials were conducted from 2004-2006, testing ALS herbicides for preemergence and early postemergence activity on newly seeded turfgrasses, using four species: Riviera bermuda, Zenith and Companion zoysia, L- 93 creeping bentgrass, and Poa annua L. Data collected were phytotoxicity and percent turf cover. Bermuda and zoysia herbicides were metsulfuron-methyl (42 g ha-1), trifloxysulfuron (29 g ha-1), flazasulfuron (53 g ha-1), foramsulfuron (30 g ha-1), bispyribac-sodium (112 g ha-1), and rimsulfuron (35 g ha-1). Treatments occurred the day of seeding and two-three weeks after seeding. Flazasulfuron, trifloxysulfuron and bispyribac-sodium caused significant damage in all treatments. Data suggests that bermuda and zoysia are tolerant of seedling treatments of foramsulfuron, rimsulfuron, and metsulfuron-methyl at these rates. Bentgrass and P. annua herbicides were foramsulfuron (15 and 30 g ha-1), siduron (2803 g ha-1), bispyribac-sodium (49 g ha-1), and paclobutrazol (281 g ha-1). Treatments occurred the day of seeding, two and four weeks after seeding. Foramsulfuron at 15 and 30 g ha-1 caused significant damage regardless of when it was applied. Data suggests that bentgrass and P. annua are tolerant of seedling treatments of siduron, paclobutrazol, and bispyribac-sodium at these rates.
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Myers, Jonathan Andrew. "Seedling carbohydrate storage, survival, and stress tolerance in a neotropical forest." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0009262.

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Ali, Rao Sajjad. "The potential for breeding Zea mays (L.) for saline conditions." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387451.

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Oddie, Rachel Louise Annabelle. "Eucalyptus camaldulensis x globulus hybrids for saline land: Production, seedling growth and salt / waterlogging tolerance." Thesis, Oddie, Rachel Louise Annabelle (1996) Eucalyptus camaldulensis x globulus hybrids for saline land: Production, seedling growth and salt / waterlogging tolerance. PhD thesis, Murdoch University, 1996. https://researchrepository.murdoch.edu.au/id/eprint/52423/.

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The rapid development of Eucalyptus globulus Labill. plantations for the paper and pulp industry and the increasing problem of dry land salinity in the south west of Western Australia, stimulated the development of a breeding programme aimed at producing a Eucalyptus L'Herit. hybrid that combines the salt / waterlogging tolerance of selected E. camaldulensis Dehnh. clones with the high pulp quality and yield of selected E. globulus subsp. globulus families. Controlled pollination techniques were used to produce intraspecific and interspecific hybrids. Unilateral cross incompatibility was observed between the two species. When E. globulus was used as the female parent E. camaldulensis pollen tubes failed to grow the entire length of E. globulus styles. However when E. camaldulensis was used as the female parent, interspecific crosses were successful. Five E. camaldulensis salt tolerant clones and four E. globulus families (three with known pedigree) were used to produce the crosses. E. camaldulensis flowers were emasculated just before operculum shed. Stigma receptivity, assessed by seed production, peaked in E. camaldulensis three days after emasculation. This coincided with the style turning red and the stigma becoming enlarged, yellow and sticky. Reasonably high levels of seed (> 25 seeds per capsule and > 65 % capsule set) could also be produced when flowers were pollinated before or after day three (days 0 - 5). Pollen placed on green, dry stigmas (days 0-2) remained ungerminated until stigmas began to enlarge and become sticky. The timing of stigma receptivity varied between the E. camaldulensis genotypes. The number of seeds produced per capsule when E. camaldulensis was selfed was 87 % less than when the clones were outcrossed. The interspecific hybrids showed a 77 % reduction in seed set compared to outcrossed E. camaldulensis. In both cases the mechanism of the partial incompatibility was not operating in the style. Further barriers to the hybridization of E. camaldulensis and E. globulus were manifested as a high percentage of seedlings with abnormalities compared to outcrossed E. camaldulensis. The intensity of barriers to interspecific hybridization varied, with families exhibiting from 50 to 97 % abnormal progeny. Seedlings at the two leaf stage and at six to eight months old were scored for a number of morphological characters. These were cotyledon length, cotyledon width, depth of cotyledon emargination, petiole length, lamina length, lamina width at the widest point, the vertical distance between the axillary buds at the fifth node and leaf angle (angle between the main stem and the midvein of the lamina). Overall the morphology of the hybrids (assessed by these characters) tended to be intermediate between the two parents, but more like E. globulus than E. camaldulensis. A small number of seedlings produced from E. camaldulensis x globulus crosses were morphologically very similar to E. camaldulensis. Allozyme analysis was used to determine the parentage of these individuals. Of the six enzyme systems studied malate dehydrogenase (MDH, E.C. 1.1.1.37) and 6-phosphogluconate dehydrogenase (6PGD, E.C. 1.1.1.44) were the most useful in identifying E. camaldulensis x globulus hybrids. The seedlings from hybrid families with similar morphology to E. camaldulensis were identified as E. camaldulensis. All other seedlings from hybrid families were clearly of hybrid origin. The possible cause of the seed contamination in the controlled crosses is discussed. Seven month old seedlings were screened for salt / waterlogging tolerance in a glasshouse trial. Seedlings were placed in tanks and flooded to the sand level in the pots with one fifth Hoagland nutrient solution number two for one week. The following and each subsequent week 50 mM NaCl was added to the tanks until the NaCl concentration reached 350 mM. This concentration was held for three weeks. E. camaldulensis had a greater salt / waterlogging tolerance than E. globulus based on survival and height growth rate. The performance of the hybrid families was intermediate between the two parental species. Genotypes with superior tolerance of saline waterlogging were micropropagated for further field trials. The potential of selected E. camaldulensis x globulus genotypes is discussed in light of the preliminary results of the breeding programme.
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Mwando, Edward Kulecho. "The genetics of barley (Hordeum vulgare) salinity tolerance during germination and the instantaneous seedling endurance." Thesis, Mwando, Edward Kulecho (2021) The genetics of barley (Hordeum vulgare) salinity tolerance during germination and the instantaneous seedling endurance. PhD thesis, Murdoch University, 2021. https://researchrepository.murdoch.edu.au/id/eprint/60357/.

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Salinity limits crop production through osmotic and ionic stress in combination with oxidative strain and nutrient imbalance. Osmotic tolerance, ionic exclusion, and tissue tolerance are some of the adaptive mechanisms in plants when exposed to salinity stress. These physiological adaptive mechanisms are quantitative in nature and are manifested genetically by affecting ~ 8% of genes expression. Barley, the fourth most important cereal crop in the world, is relatively salinity tolerant. However, salinity causes a significant reduction in its growth and grain yield. Adaptation to salinity in barley is varied with growth stage where germination and early growth stages are the most sensitive. This is because excessive salt accumulation in the rhizosphere affects the germinating seed and the subsequent developmental processes including revitalization of plants development after exposure to salinity stress during the sprouting stage. Studies are yet to close the lack of information between the germination and/or seedling stage salinity tolerance, and the genotypic differences in developing young plants regeneration after exposure to salinity stress. The current study explored the genetics of salinity tolerance during the germination stage and the seedling survival in barley after germination under salinity stress (NaCl). To detect the genetic loci and candidate genes responsible for salinity tolerance in barley during germination and early growth stages, four barley populations comprising of a diversity panel of 350 accessions from across the globe, two doubled haploid (DH) populations (CM72/Gairdner and Skiff/CM72), and a back-cross population of CM72/Gairdner/*Spartacus CL were used for phenotyping and mapping. These germplasm sets were exposed to different levels of salinity stress (75, 90, 120 AND 150 mM NaCl) along with a control treatment (deionized water) and various phenotypic traits recorded at germination and early seedling stages. Genome-Wide Association (GWAS) analysis was conducted on a diversity panel of 350 accessions using ~24,000 genetic markers, where 19 Quantitative Traits Nucleotides (QTNs) were detected across all 7 barley chromosomes and 4 genes predicted for salinity tolerance at germination. A study with CM72/Gairdner DH population mapped six Quantitative Traits Loci (QTLs) on chromosomes 1H, 3H and 4H for traits associated with seedling survival under salinity stress. Three QTLs on 1H (1) and 3H (2) with closely linked significant markers that were detected in more than one salinity survival traits were proposed as the regions with highest probability of having candidate genes. To narrow down the location of genetic regions associated with salinity tolerance at germination on chromosome 2H, a major QTL was fine–mapped using CM72/Gairdner and Skiff/CM72 DH populations, F2 and F3 generations of CM72/Gairdner/*Spartacus CL to a region of ~ 0.341 Mb and designed 2 diagnostic markers. Further, this study reported two Receptor-like protein kinase 4 as the candidate genes for enhanced germination under salinity stress. The diversity of seven reported genes in barley was explored further in 40 different species where three of them; dehydration-responsive element-binding (DREB) protein, somatic embryogenesis receptor-like kinase and aquaporin genes, were found to be the most varied. While all three gene families show great diversity in most plant species, the DREB gene family was more diverse in barley than in wheat and rice. Sixty-five barley homolog genes were identified from salinity tolerance genes characterized in Arabidopsis, maize, rice, soybean, and wheat. Besides, the homologs have been reported to express themselves in first three barley’s developmental stages. The results of this study provide new genetic resources and information for further functional characterization of the identified candidate genes and to improve salinity tolerance at germination and early seedling stage via genomic and marker-assisted selection (MAS) in barley. The findings in this thesis together with other existing information will facilitate breeding and release of new high yielding barley varieties that can grow in extreme environment including saline soils of the world.
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Dowling, Christopher W. "Seed and Seedling Tolerance of Cereal, Oilseed, Fibre and Legume Crops to Injury from Banded Ammonium Fertilizers." Thesis, Griffith University, 1998. http://hdl.handle.net/10072/366485.

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Processes causing crop establishment damage from ammonium (NH4+) fertilizer placed in close proximity to seed at sowing are generally poorly understood within farming communities of eastern Australia. Currently, the information used to assess establishment hazard includes nitrogen (N) tolerance for a limited range of crop species. Other factors include the N concentration of fertilizer products, with adjustment of the rate expected to be tolerated on the basis of soil moisture and application equipment. Current recommendations were adapted from North American research spanning a period from the start of the century until the 1990s and some recent Australian research (1960s to 1980s) for a limited range of crops and fertilizer types. The incidence of seedling damage from N fertilizer and fertilizer containing other nutrients appears to have grown in recent years. This may be attributed to use of a wider range of NH4+ and other fertilizers, a trend for at-sowing application in zero-tillage and expansion of areas of declining soil fertility, particularly N fertility. Other factors include the sowing of new crops with greater fertilizer sensitivity, low tolerance to establishment loss for high value genetically modified seed and modern designs of sowing and application equipment. The major objective of this research was to investigate ammonia (NH3) tolerance of 10 crop species of importance for eastern Australian cropping systems (maize, Zea mays L.; cotton, Gossypium hirsutum L.; wheat, Triticum aestivum L.; barley, Hordeum vulgare L.; chickpea, Cicer arietinum L.; sorghum, Sorghum bicolor (L.) Moench; canary, Phalaris canariensis L.; canola, Brassica napus L.; panicum, Setaria italica L. and sunflower, Helianthus annuus L.). Experiments were designed to highlight differences among crops in NH3 toxicity and osmotic damage potential for commonly used NH4+ fertilizers. Various strategies were then tested to maintain plant populations within commercially acceptable ranges when affected by NH3 toxicity and/or high osmotic pressure. Tolerance of seeds to NH3 toxicity was evaluated in the field and for atmospheric exposure. Response of various crop species to atmospheric-NH3 exposure showed that certain species responded differently in their germination, coleoptile growth and radicle growth in a closed system. Using these 3 parameters as indices of crop response to NH3 toxicity revealed different ranking for some species; the same species showed a different critical NH4+ concentration for each parameter. Exposing seeds above 200 x 10-4 M NH4OH for 72 h was sufficient to significantly reduce or inhibit germination of all 10 species tested. Seed of most species were unaffected by exposure above 20 x 10-4 M NH4OH. Species rank, combining tolerance for germination, coleoptile growth and radicle growth was established to relate to likely performance in the field. Decreasing order of tolerance for monocot species was: maize > sorghum > wheat = barley > panicum > canary and for dicot species chickpeas > cotton > sunflowers > canola. A range of physical and chemical seed characteristics was correlated with NH3 tolerance to investigate tolerance mechanisms. For monocot species, tolerance was related to the seed surface area/volume ratio suggesting that diffusion resistance was an important parameter whereas for dicot species N concentration of seed was negatively correlated with tolerance. In field experiments where NH4+-fertilizers were placed with seeds, difference between species in their tolerance of atmospheric-NH3 was insufficient to describe effects of NH4+-fertilizers on crop emergence. Crop species fell into 3 response categories; high (maize, sorghum, barley and wheat), medium (cotton, canary and sunflower) or low (canola, chickpea and panicum) tolerance to soil NH4+-N. Soil NH4+-N concentrations tolerated by the medium and low tolerance group was 50 % and 15 to 25 % respectively, that of the high tolerance group. Generally, NH3 tolerance response for species such as wheat, barley and sorghum was found similar to current recommendations for urea (~0.5 g/m N as urea) but there were significantly different responses to NH4+-N from different NH4+-fertilizer products, that are not recognised in current recommendations. Crop species were ranked for sensitivity to mono-ammonium phosphate (MAP), di-ammonium phosphate (DAP), triple superphosphate (TSP), urea and ammonium nitrate, and categorised according to the fertilizer rate at which significant establishment damage occurred. Ranking of crop species for NH3 toxicity was generally similar across experiments but the NH4+-N rate tolerated varied with experimental conditions. Urea and DAP caused larger reductions in establishment than equivalent NH4+-N rates from MAP or ammonium nitrate. The "safe" rate for ammonium nitrate (1 g/m NH4+-N) was approximately twice that of urea at equivalent NH4+-N rates. Usually between 20 and 30 % more NH4+-N was tolerated for MAP than for DAP. In the absence of NH3 toxicity, osmotic effects of fertilizer products delayed and occasionally inhibited germination. There was significant difference among species in osmotic tolerance; cotton, maize and sorghum (< -0.3 MPa) were more tolerant than sunflower or soybean (> -0.2 MPa). Strategies to improve crop establishment in the presence of NH4+ fertilizer such as increasing seeding rate, adding water to the seed furrow, changing fertilizer N source and chemically modifying hydrolysis of urea were identified and tested. For low to moderate rates of seed placed NH4+-N, increasing barley seeding rate from 25 to 40 kg/ha was found to be successful strategy to maintain establishment when urea rate was increased from 1.1 to 2.3 g/m of seed row. Changing the fertilizer N source and modifying hydrolysis of urea were successful in lowering soil NH4+ around the seed and thus reducing establishment losses, but osmotic effects also limit the maximum fertilizer application rates. The added cost of these strategies may prevent their widespread adoption. Complex interactions between crop species, fertilizer product, soil texture and moisture, and application equipment highlighted by the results of these experiments, suggest that simple decision tools are insufficient to provide fertilizer recommendations that meet the demands of modern agriculture. A computer based decision support programme, Fertsafe, was developed during this study from experiments conducted and papers reviewed, to provide "safe rate" recommendations to apply fertilizer at sowing for a range of crop species, fertilizers, soils and sowing conditions of eastern Australia. Changes to fertilizer application equipment, other crops and fertilizer products will require ongoing research continuously improve and update this decision support tool.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>Australian School of Environmental Studies<br>Full Text
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Parajuli, Suman. "Influence of Tomato (Solanum lycopersicum L.) Seedling Grafting on Plant Growth, Fruit Yield and Quality, and Disease Tolerance." Thesis, North Dakota State University, 2019. https://hdl.handle.net/10365/31651.

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Influence of tomato (Solanum lycopersicum L.) seedling grafting on the plant growth, fruit yield and quality, and disease tolerance were investigated using 3 cultivars (Big Beef, Celebrity, Cannonball) as scions and two Solanum species (B-blocking, Maxifort) as a rootstock in a randomized complete block design with three replications. The grafted plants were statistically higher in values for stem diameter, leaf chlorophyll, and fruit carotenoid contents. Similarly, the scion/rootstock combination ‘Big Beef/Maxifort’ and ‘Big Beef/B-blocking’ had prolonged days to maturity and gives a higher yield than the non-grafted ‘Big Beef’. Grafting seedling on ‘Maxifort’ and ‘B-blocking’ rootstocks improves the fruit quality like titratable acidity (TA), fruit firmness, but didn’t alter the pH, total soluble solid (TSS), lycopene and TSS/TA. Also, grafted treatment ‘Big Beef/Maxifort’ was found to be a highly disease resistant treatment when compared to the ‘Big Beef’ control with mean relative effect 0.074.
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Kibret, Kidist Bogale [Verfasser]. "Systems biological analysis of seedling vigour and osmotic stress tolerance in oilseed rape (Brassica napus L., Brassicaceae) / Kidist Bogale Kibret." Gießen : Universitätsbibliothek, 2017. http://d-nb.info/113657008X/34.

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Jibo, Abdullahi Umar. "Variation in drought tolerance and morphological plasticity among two provenances of Acacia senegal (Senegalia senegal) seedling in North Eastern Nigeria." Thesis, University of Aberdeen, 2015. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=227119.

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Books on the topic "Seedling Tolerance"

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Tauer, Charles G. Seed source influences juniper seedling survival under severe drought stress. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, 1987.

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Muturi, Gabriel Mukuria. Provenance variation of salt tolerance and seedling nutrition in acacia tortillas (Forsk.) Hayne. National Library of Canada, 1993.

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Biring, Balvinder Singh. Tolerance of black spruce seedlings to the herbicide glyphosate. National Library of Canada = Bibliothèque nationale du Canada, 1991.

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Heidmann, L. J. Effect of prolonged drought on water relations of ponderosa pine seedlings growing in basalt and sedimentary soils. U.S. Dept. of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station, 1992.

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Tauer, C. G. Seed source influences juniper seedling survival under severe drought stress. 1987.

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Teklemariam, Thomas Alemu. Effects of near-ambient utlraviolet-B radiation on seedling tolerance of extreme temperatures. 2002.

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Muturi, Gabriel M. Provenance variation of salt tolerance and seedling nutrition in acacia tortilis (Forsk.) Hayne. 1994.

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Aldous, David E., and Ian H. Chivers. Sports Turf and Amenity Grasses. CSIRO Publishing, 2002. http://dx.doi.org/10.1071/9780643090019.

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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. &#x0D; 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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Sumaryono. Differential tolerance of woody nursery crop seedlings to napropamide. 1985.

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Northern hardwood notes: Relative tolerance of hardwood and associated conifer seedlings. U.S. Dept. of Agriculture], North Central Forest Experiment Station, 1987.

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Book chapters on the topic "Seedling Tolerance"

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Salami, Robab, Masoumeh Kordi, Nasser Delangiz, Behnam Asgari Lajayer, and Tess Astatkie. "Seedling and Seed Priming in Regulating Secondary Metabolite Level for Stress Tolerance." In Biology and Biotechnology of Environmental Stress Tolerance in Plants. Apple Academic Press, 2023. http://dx.doi.org/10.1201/9781003346173-13.

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Ghosh, Subir, Kuntal Bera, Puspendu Dutta, and Sanjoy Sadhukhan. "Seed Priming and Seedling Pre-Treatment in RegulatingSecondary Metabolism for Stress Tolerance." In Biology and Biotechnology of Environmental Stress Tolerance in Plants. Apple Academic Press, 2023. http://dx.doi.org/10.1201/9781003346173-14.

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Li, Xuemei, and Lihong Zhang. "SA and PEG-Induced Priming for Water Stress Tolerance in Rice Seedling." In Advances in Intelligent and Soft Computing. Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-27537-1_104.

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Wu, P., A. Luo, J. Zhu, J. Yang, N. Huang, and D. Senadhira. "Molecular markers linked to genes underlying seedling tolerance for ferrous iron toxicity." In Plant Nutrition for Sustainable Food Production and Environment. Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-009-0047-9_255.

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Sahoo, Smita, Pankaj Borgohain, Bedabrata Saha, Debojyoti Moulick, Bhaben Tanti, and Sanjib Kumar Panda. "Seed Priming and Seedling Pre-treatment Induced Tolerance to Drought and Salt Stress: Recent Advances." In Priming and Pretreatment of Seeds and Seedlings. Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-8625-1_12.

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Sarsu, Fatma. "Screening Protocols for Heat Tolerance in Rice at the Seedling and Reproductive Stages." In Pre-Field Screening Protocols for Heat-Tolerant Mutants in Rice. Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-77338-4_2.

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Das, Priyanka, Rajeev N. Bahuguna, Rohit Joshi, Sneh Lata Singla-Pareek, and Ashwani Pareek. "In search of mutants for gene discovery and functional genomics for multiple stress tolerance in rice." In Mutation breeding, genetic diversity and crop adaptation to climate change. CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0045.

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Abstract Mutation breeding is a commanding tool, which has been adapted to generate altered genetic material to study functional genomics, including understanding the molecular basis of stress tolerance. Hitherto, several rice lines have been generated through mutagenesis and the mutated genes responsible for the 'gain of function' in terms of plant architecture, stress tolerance, disease resistance and grain quality have been characterized. Oryza sativa L. cv. IR64 is a high-yielding rice cultivar but sensitive to abiotic stresses such as acute temperatures, salinity and drought. In this study, a population of rice IR64 mutants was generated using gamma irradiation. The population was then subjected to a preliminary phenotypic screening under abiotic stresses such as heat and salinity at the seedling stage. On the basis of root length, shoot length, fresh weight, dry weight and chlorophyll measurements, we identified eight 'gain-of-function' mutant lines and used them for further biochemical and molecular characterization. Phenotyping results demonstrated that the identified mutant plants have gained the potential to thrive under heat and salinity conditions. This information would be of wide scientific interest and helpful for developing novel cultivars able to maintain yield in saline, hot and dry areas.
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Gomez-Pando, Luz, Jesus Bernardo-Rojas, Denisse Deza-Montoya, Martha Ibañez-Tremolada, and Enrique Aguilar-Castellanos. "Mutation induction to improve quinoa (Chenopodium quinoa) resistance to downy mildew (Peronospora variabilis)." In Mutation breeding, genetic diversity and crop adaptation to climate change. CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0019.

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Abstract Quinoa is an important crop due to its nutritional characteristics (better than cereals) and its tolerance to abiotic stresses. However, various factors such as high susceptibility to diseases, especially downy mildew caused by Peronospora variabilis, limit its agricultural performance. Genetic improvement of quinoa could reduce the need to use fungicides for this crop and maintain the organic quality of Peruvian production in small-scale farms. Seeds of var. 'Amarilla Marangani', irradiated with 150 and 250 Gy of gamma-rays (<sup>60</sup>Co), were evaluated in two experimental locations in Peru: coastland at La Molina and highland at Huancayo. Resistance to downy mildew and other agricultural traits in the M<sub>3</sub> and M<sub>4</sub> generations was studied. In both locations, downy mildew was observed in susceptible plants under natural infection, from the seedling stage to plant maturity. At the coastland site, six mutants with 30% leaf infection were obtained in the progeny of plants exposed to 150 Gy. Five additional mutants with 40% leaf infection were found in the progeny of plants exposed to 250 Gy. In the highland trial, only seven lines were identified with 30% severity (foliar area with symptoms) among the plants from the 150 Gy experiment. The parent materials showed 70-80% disease severity. Mutant lines with quantitative resistance and tolerance to downy mildew, high yield potential, reduced duration, shorter plant height, altered inflorescence shape and grain colour mutations were selected from both doses. This study showed that quantitative resistance and tolerance to downy mildew could be obtained in quinoa and this resulted in increased grain yields.
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Lula, Mikolaj, Kjersti Holt Hanssen, Martin Goude, et al. "Regeneration." In Managing Forest Ecosystems. Springer Nature Switzerland, 2024. https://doi.org/10.1007/978-3-031-70484-0_3.

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Abstract In the context of continuous cover forestry (CCF), natural regeneration is the preferred form of regeneration, but it is a long-lasting and complex process. Shelter density has a large effect on the regeneration process and results. The selection system, particularly suited for shade-tolerant species like Norway spruce, relies on continuous regeneration and ingrowth into larger size classes. Regeneration and ingrowth rates vary significantly among stands, influenced by site and historical factors, with no clear relationship to current stand conditions. In the group system, edge trees influence regeneration by providing seeds, checking weed growth, and exerting competition. Regeneration in gaps is generally satisfactory for both Norway spruce and Scots pine. However, seedlings usually grow slower, especially close to the gap edges. The shelterwood system promotes regeneration through a successive, uniform opening of the canopy. Shelter trees provide seeds, and reduce seedling damage and competition from ground vegetation. On the other hand, the remaining overstorey shelter trees reduce seedling growth. Conversion to the selection system initiates regeneration in young stands, aiming for slow and steady regeneration. Given the rapid growth and crown closure in young stands, frequent manipulation of shelter density is essential during conversion, for example by opening small gaps.
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Gutterman, Yitzchak, and Sabrina Gozlan. "Afterripening, Amounts of Rain for Germination, and Seedling Drought Tolerance, of Local and Edaphic Ecotypes of Hordeum spontaneum C. Koch from Israel." In Evolutionary Theory and Processes: Modern Perspectives. Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4830-6_25.

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Conference papers on the topic "Seedling Tolerance"

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Wu, Jun-jiang, Peng-fei Xu, Li-jun Liu, et al. "Mapping QTLs for Phosphorus-deficiency Tolerance in Soybean at Seedling Stage." In 2012 International Conference on Biomedical Engineering and Biotechnology (iCBEB). IEEE, 2012. http://dx.doi.org/10.1109/icbeb.2012.269.

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Li, Xiaoying, and Bo Zhang. "Improving Edamame Seedling Establishment by Determining the Optimal Temperature." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/ybzg7716.

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Demand in the United States for edamame has increased over the past two decades. Edamame has become the second largest soyfood consumed in the US (25,000-30,000 tons annually). While domestic edamame production is slowly increasing, at least 70% of edamame consumed in the US is imported. Poor crop establishment is a major problem limiting edamame production. Seedling emergence ranges from 50-85%, which is lower than that of grain-type soybean ( &gt;85%). Seedling stand can be improved by growing under the optimal temperature. Up to now, edamame is planted still based on grain-type soybean recommendations. The objective of this study was to determine the minimum, optimum, and maximum emergence temperatures of edamame. It will provide a scientific basis for deciding the best planting time of edamame, ultimately improving its seedling stand in the field. In this study, two edamame cultivars (VT Sweet and UA Kirksey) were tested for their seedling emergence percentage and emergence rate (i.e., emergence speed) at 5, 7, 10, 13, 16, 19, 21, 23, 25, 27, 29, 32, 35, 38, 41, 45 °C (soil temperature) using the LabFieldTM Simulation Table. Two grain-type soybean cultivars (MFS-48P1 and USF5618v) were checks. The results showed that the optimal temperature range for edamame seedling emergence is 25-32 °C, which is lower than that of grain-type soybean (29-36 °C). Soybean did not emerge at around 4 °C, however, edamame seeds may have a higher tolerance to low temperature compared with grain-type soybean. The maximum temperature varied little among soybean types, with an average of 41.08 °C. In addition, edamame needs more thermal time to emerge. The results indicate that edamame has a different emergence response to temperature compared with grain-type soybean. Edamame should be planted earlier than grain-type soybean and later planting may reduce edamame seedling emergence.
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Mogîlda, Anatolii. "The effect of water stress on sesame (sesamum indicum l.) Samples from the m3 generation in the conditions of it’s artificial modeling." In Scientific International Symposium “Advanced Biotechnologies - Achievements and Prospects” (VIth Edition). Institute of Genetics, Physiology and Plant Protection, 2022. http://dx.doi.org/10.53040/abap6.2022.67.

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Sesame (Sesamum indicum L.) is one of the most important oil crops widely cultivated in different regions of the world. For many centuries, sesame seeds have been used as a source of oil, protein, vitamins and minerals for human and animal nutrition [4]. Unlike other crops, sesame is considered to be more drought tolerant [5]. However, drought often occurs together with heat or high temperatures and significantly affects sesa-me production. Detrimental effects on sesame seed production and quality are significantly observed when water stress occurs, especially at the germination and flowering stages [3]. Severe or prolonged drought negatively influences sesame productivity by reducing the num-ber of capsules per plant, yield and oil quality [1]. Drought stress can also affect the level of secondary metabolites and morphophysiological characteristics of sesame seeds. Seed ger-mination is the first critical and most sensitive stage of the plant life cycle [3] due to its direct and strong correlation with seedling establishment and early growth. As a result of climate change, there is an increased frequency of drought throughout the crop cycle, including the germination stage. Thus, there is a need to improve crop drought tolerance through breeding and selection of suitable germplasm to be used in the development of adapted cultivars that could enable sustai-nable and competitive sesame cultivation. This work was carried out with the aim of comparative testing of sesame samples obtained by the induced mutagenesis (Gy) method, after resistance to osmotic stress under the conditions of its experimental modeling by using the osmotically active substance PEG 6000.
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Caus, Maria, Alexandru Dascaliuc, and Pantelimon Borozan. "Activitatea catalazei, peroxidazei și peroxidării lipidelor în rădăcinile porumbului sub influența șocului termic și a reglalgului." In Scientific International Symposium "Plant Protection – Achievements and Perspectives". Institute of Genetics, Physiology and Plant Protection, Republic of Moldova, 2023. http://dx.doi.org/10.53040/ppap2023.44.

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In recent years, due to the climate changes, the growth and development of corn is affected by heat stress, especially at an early stage of ontogeny. Influence of biostimulant Reglalg, used for seed pretreatment of maize hybrids Por. 310 and Por. 374 before exposure to heat shock (HS) at 50°C for 30 min, on catalase (CAT), peroxidase (PO), and lipid peroxidation (LPO) of root seedlings was studied. Compared to the Reglalg variants, root growth of control seedlings was more strongly affected by HS, since the activity levels of CAT, PO and MDA content in the roots were higher. This demonstrates the beneficial effects of Reglalg in increasing maize tolerance to HS.
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Wang, Xuefeng, and Masayuki Hirafuji. "Salt tolerance research of shinyleaf yellowhorn seedlings based on the pixel changes." In 2010 3rd International Congress on Image and Signal Processing (CISP). IEEE, 2010. http://dx.doi.org/10.1109/cisp.2010.5648095.

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"Molecular Genetic Method of Assessing Drought Tolerance in spring and Winter Wheat Seedlings." In 3rd International Conference on Civil, Biological and Environmental Engineering. International Institute of Chemical, Biological & Environmental Engineering, 2016. http://dx.doi.org/10.15242/iicbe.c0216017.

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Hui Li and Nanning Duan. "Effects on the rice seedling growth by cadmium tolerant bacteria under cadmium stress." In 2011 International Conference on Remote Sensing, Environment and Transportation Engineering (RSETE). IEEE, 2011. http://dx.doi.org/10.1109/rsete.2011.5965930.

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TURK, HULYA, MUCIP GENISEL, and SERKAN ERDAL. "Estrone induced biochemical and molecular changes confers tolerance to boron toxicity in wheat seedlings." In Third International Conference on Advances in Bio-Informatics and Environmental Engineering - ICABEE 2015. Institute of Research Engineers and Doctors, 2015. http://dx.doi.org/10.15224/978-1-63248-078-1-04.

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Voskoboinik, Mihail. "FOREST-SEED PLANTATIONS: SPECIES COMPOSITION AND PLANTING SCHEMES IN TEMPERATE CLIMATE ZONE CONDITIONS." In Adaptation of forestry to climate change: nature-oriented solutions and digitalization. Forestry – 2024. FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov, 2025. https://doi.org/10.58168/ffys2024_21-27.

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The temperate climate zone is one of the most suitable places to create seed plantations due to its clear seasons and sufficient rainfall. The winter here is not too cold, with temperatures around -10 °C, and in summer the temperature reaches 18-22 °C. These conditions are ideal for the growth of woody plants and allow a variety of tree species to develop harmoniously. Common pine, common spruce, oak, birch and larch are among the most suitable for seed plantations in temperate climates. These trees are well adapted to temperature changes and can grow successfully even in difficult conditions. To create forest seed production facilities, it is advisable to use large-sized seedlings with a lump of soil. They provide a higher probability of successful rooting and rapid growth of trees. Large-sized seedlings with a lump of soil have many advantages. They tolerate transplanting more easily, as their roots are protected from damage, which contributes to a better living. In addition, the use of such seedlings can improve the quality of future trees, as they are grown from high-quality seeds. This technology makes pine, spruce, oak, birch and larch a rational choice for creating seed plantations in the temperate climate of our country.
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Zhang, Guo-liang. "Notice of Retraction: Screening of Tolerant Rice Genotypes to 1,2,4-Trichlorobenzene Stress at Seedling Stag." In 2011 5th International Conference on Bioinformatics and Biomedical Engineering. IEEE, 2011. http://dx.doi.org/10.1109/icbbe.2011.5781449.

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Reports on the topic "Seedling Tolerance"

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Blume, Christopher, Nick E. Christians, Andrew H. Hoiberg, and David D. Minner. Imprelis 2SL Crabgrass and Broadleaf Weed Efficacy and Seedling Tolerance. Iowa State University, Digital Repository, 2011. http://dx.doi.org/10.31274/farmprogressreports-180814-858.

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Moore, Gloria A., Gozal Ben-Hayyim, Charles L. Guy, and Doron Holland. Mapping Quantitative Trait Loci in the Woody Perennial Plant Genus Citrus. United States Department of Agriculture, 1995. http://dx.doi.org/10.32747/1995.7570565.bard.

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As is true for all crops, production of Citrus fruit is limited by traits whose characteristics are the products of many genes (i.e. cold hardiness). In order to modify these traits by marker aided selection or molecular genetic techniques, it is first necessary to map the relevant genes. Mapping of quantitative trait loci (QTLs) in perennial plants has been extremely difficult, requiring large numbers of mature plants. Production of suitable mapping populations has been inhibited by aspects of reproductive biology (e.g. incompatibility, apomixis) and delayed by juvenility. New approaches promise to overcome some of these obstacles. The overall objective of this project was to determine whether QTLs for environmental stress tolerance could be effectively mapped in the perennial crop Citrus, using an extensive linkage map consisting of various types of molecular markers. Specific objectives were to: 1) Produce a highly saturated genetic linkage map of Citrus by continuing to place molecular markers of several types on the map. 2) Exploiting recently developed technology and already characterized parental types, determine whether QTLs governing cold acclimation can be mapped using very young seedling populations. 3) Determine whether the same strategy can be transferred to a different situation by mapping QTLs influencing Na+ and C1- exclusion (likely components of salinity tolerance) in the already characterized cross and in new alternative crosses. 4) Construct a YAC library of the citrus genome for future mapping and cloning.
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Guy, Charles, Gozal Ben-Hayyim, Gloria Moore, Doron Holland, and Yuval Eshdat. Common Mechanisms of Response to the Stresses of High Salinity and Low Temperature and Genetic Mapping of Stress Tolerance Loci in Citrus. United States Department of Agriculture, 1995. http://dx.doi.org/10.32747/1995.7613013.bard.

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The objectives that were outlined in our original proposal have largely been achieved or will be so by the end of the project in February 1995 with one exception; that of mapping cold tolerance loci based on the segregation of tolerance in the BC1 progeny population. Briefly, our goals were to 1) construct a densely populated linkage map of the citrus genome: 2) map loci important in cold and/or salt stress tolerance; and 3) characterize the expression of genes responsive to cold land salt stress. As can be seen by the preceding listing of accomplishments, our original objectives A and B have been realized, objective C has been partially tested, objective D has been completed, and work on objectives E and F will be completed by the end of 1995. Although we have yet to map any loci that contribute to an ability of citrus to maintain growth when irrigated with saline water, our very encouraging results from the 1993 experiment provides us with considerable hope that 1994's much more comprehensive and better controlled experiment will yield the desired results once the data has been fully analyzed. Part of our optimism derives from the findings that loci for growth are closely linked with loci associated with foliar Cl- and Na+ accumulation patterns under non-salinization conditions. In the 1994 experiment, if ion exclusion or sequestration traits are segregating in the population, the experimental design will permit their resolution. Our fortunes with respect to cold tolerance is another situation. In three attempts to quantitatively characterize cold tolerance as an LT50, the results have been too variable and the incremental differences between sensitive and tolerant too small to use for mapping. To adequately determine the LT50 requires many plants, many more than we have been able to generate in the time and space available by making cuttings from small greenhouse-grown stock plants. As it has turned out, with citrus, to prepare enough plants needed to be successful in this objective would have required extensive facilities for both growing and testing hardiness which simply were not available at University of Florida. The large populations necessary to overcome the variability we encountered was unanticipated and unforeseeable at the project's outset. In spite of the setbacks, this project, when it is finally complete will be exceedingly successful. Listing of Accomplishments During the funded interval we have accomplished the following objectives: Developed a reasonably high density linkage map for citrus - mapped the loci for two cold responsive genes that were cloned from Poncirus - mapped the loci for csa, the salt responsive gene for glutathione peroxidase, and ccr a circadian rhythm gene from citrus - identified loci that confer parental derived specific DNA methylation patterns in the Citrus X Poncirus cross - mapped 5 loci that determine shoot vigor - mapped 2 loci that influence leaf Na+ accumulation patterns under non-saline conditions in the BC1 population - mapped 3 loci that influence leaf Na+ accumulation paterns during salt sress - mapped 2 loci that control leaf Cl- accumulation patterns under non-saline conditions - mapped a locus that controls leaf Cl- accumulation patterns during salt stress Screened the BC1 population for growth reduction during salinization (controls and salinized), and cold tolerance - determined population variation for shoot/root ratio of Na+ and Cl- - determined levels for 12 inorganic nutrient elements in an effort to examine the influence of salinization on ion content with emphasis on foliar responses - collected data on ion distribution to reveal patterns of exclusion/sequestration/ accumulation - analyzed relationships between ion content and growth Characterization of gene expression in response to salt or cold stress - cloned the gene for the salt responsive protein csa, identified it as glutathione peroxidase, determined the potential target substrate from enzymatic studies - cloned two other genes responsive to salt stress, one for the citrus homologue of a Lea5, and the other for an "oleosin" like gene - cold regulated (cor) genes belonging to five hybridization classes were isolated from Poncirus, two belonged to the group 2 Lea superfamily of stress proteins, the others show no significant homology to other known sequences - the expression of csa during cold acclimation was examined, and the expression of some of the cor genes were examined in response to salt stress - the influence of salinization on cold tolerance has been examined with seedling populations - conducted protein blot studies for expression of cold stress proteins during salt stress and vice versa
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4

Veilleux, Richard, and David Levy. Potato Germplasm Development for Warm Climates. United States Department of Agriculture, 1992. http://dx.doi.org/10.32747/1992.7561057.bard.

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Complex potato hybrids derived from crosses between cv. Atlantic and 11 clones of three genomic compositions, all with an unadapted component from previously identified heat tolerant accessions, were evaluated in the field in Israel and Virginia and in controlled environments in Israel. Heat tolerance was exhibited in the field by the ability of many of these hybrids to tuberize under severe heat stress when cv. Atlantic did not tuberize at all. The complex hybrids also exhibited fewer internal defects (heat necrosis, hollow heart) than Atlantic. Studies to determine if heat stress applied during anther culture or to pollen samples prior to pollination could affect gametic selection towards more heat tolerant progenies were also undertaken. There was some evidence of greater heat tolerance (longer survival under heat stress) in the anther-derived population that had been regenerated under heat stress. The seedlings resulting from crosses with heat-treated pollen also exhibited greater haulm growth under heat stress compared with controls. However, the poor adaption of the germplasm prevented a firm conclusion about gametic selection. The introduction of exotic germplasm into cultivated potato has considerable potential to adapt potato to nontraditional growing seasons and climates. However, such hybrids will require continued selection and evaluation to retain the traits required for commercial production.
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5

Newton, Ronald, Joseph Riov, and John Cairney. Isolation and Functional Analysis of Drought-Induced Genes in Pinus. United States Department of Agriculture, 1993. http://dx.doi.org/10.32747/1993.7568752.bard.

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Drought is a common factor limiting timber production in the U.S. and Israel. Loblolly (Pinus taeda) and alleppo pine (Pinus halepensis) seedling survival is reduced when out planted, and growth and reproduction are often hindered by periodic droughts during later stages of tree development. Molecular and gene responses to drought stress have not been characterized. The objectives were to characterize drought-induced gene clones from these pines, to determine the effects of a growth regulator on drought tolerance, ABA levels, and drought-induced gene expression in alleppo pine, and to develop procedures for loblolly pine transformation. Nearly 20 cDNA clones influenced by gradual, prolonged drought stress have been isolated. Many of these have been shown to be induced by drought stress, whereas several others are down-regulated. These are the first drought-induced genes isolated from a pine species. Two genomic clones (lp5-1 and lp3-1) have been sequenced and characterized, and each has been found to be associated with a gene family. Clone lp5 appears to code for a cell wall protein, and clone lp3 codes for a nuclear protein. The former may be associated with changing the elastic properties of the cell wall, while the latter may be involved in signal transduction and/or protection from desiccation in the nucleus. Clone lp3 is similar to a drought-induced gene from tomato and is regulated by ABA. Several DNA sequences that are specific to induction during growth-retardation in alleppo pine by uniconazole have been identified. The active DNA species is now being identified. Promoters from genomic clones, lp3 and lp5, have been sequenced. Both are functional when fused with the gus reporter gene and transferred to other plant tissues as well as responding to a simulated drought stress. Through exodeletion analysis, it has been established that the promoter ABRE element of lp3 responds to ABA and that drought-induction of lp3 expression may also involve ABA. Stable tobacco transformants carrying either the lp5 or the lp3 promoter fused to a reporter gus gene have been obtained. The lp5lgus fusion was expressed at several stages of tobacco development and differentiation including the reproductive stage. There was no difference in phenotype between the transformants and the wild type. Embryogenesis procedures were developed for slash pine, but attempts to couple this process with gene transfer and plantlet transformation were not successful. Transformation of pine using Agrobacterium appears tractable, but molecular data supporting stable integration of the Agrobacterium-transferred gene are still inconclusive.
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6

Barg, Rivka, Kendal D. Hirschi, Avner Silber, Gozal Ben-Hayyim, Yechiam Salts, and Marla Binzel. Combining Elevated Levels of Membrane Fatty Acid Desaturation and Vacuolar H+ -pyrophosphatase Activity for Improved Drought Tolerance. United States Department of Agriculture, 2012. http://dx.doi.org/10.32747/2012.7613877.bard.

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Background to the topic: In previous works we have shown that Arabidopsis and tomato over-expressing H+-pyrophosphatase show increased tolerance to drought imposed by withholding irrigation of young plants in pots (Park et al. 2005). In addition, young tobacco plants over-expressing fatty acid desaturase 3 (OEX-FAD3) also showed increasing tolerance to drought stress (Zhang et al 2005), and similarly OEX-FAD3 young tomato plants (unpublished data from ARO), hence raising the possibility that pyramiding the two could further improve drought tolerance in tomato. Based on these findings the specific objects originally set were: 1. To analyze the impact of pyramiding transgenes for enhanced fatty acid desaturation and for elevated H+-PPase activity on tomato yielding under water deficit stress conditions. 2. To elucidate the biochemical relationship between elevated desaturation of the membrane lipids and the activities of selected vacuolar transporters in the context of drought responses. 3. To explore the S. pennellii introgression lines as alternative genetic sources for drought tolerance related to enhanced fatty acid desaturation and/or H+-PPase activity. 4. Since OEX-FAD3 increases the levels of linolenic acid which is the precursor of various oxylipins including the stress hormone Jasmonate. (JA), study of the effect of this transgene on tolerance to herbivore pests was added as additional goal. The Major conclusions, solutions, and achievements are: (1) The facts that ectopic over-expression of vacuolarH+-PPases (in line OEX-AVP1) does not change the fatty acid profile compared to the parental MoneyMaker (MM) line and that elevated level of FA desaturation (by OEX-FAD3) does not change the activity of either H+-PPase, H+-ATPaseor Ca2+ /H+ antiport, indicate that the observed increased drought tolerance reported before for increase FA desaturation in tobacco plants and increased H+PPase in tomato plants involves different mechanisms. (2) After generating hybrid lines bringing to a common genetic background (i.e. F1 hybrids between line MP-1 and MM) each of the two transgenes separately and the two transgenes together the effect of various drought stress regimes including recovery from a short and longer duration of complete water withhold as well as performance under chronic stresses imposed by reducing water supply to 75-25% of the control irrigation regime could be studied. Under all the tested conditions in Israel, for well established plants grown in 3L pots or larger, none of the transgenic lines exhibited a reproducible significantly better drought tolerance compare to the parental lines. Still, examining the performance of these hybrids under the growth practices followed in the USA is called for. (3) Young seedlings of none of the identified introgression lines including the S. pennellii homologs of two of the H+-PPase genes and one of the FAD7 genes performed better than line M82 upon irrigation withhold. However, differences in the general canopy structures between the IL lines and M82 might mask such differences if existing. (4). Over-expression of FAD3 in the background of line MP-1 was found to confer significant tolerance to three important pest insects in tomato: Bordered Straw (Heliothis peltigera), Egyptian cotton leafworm (Spodoptera littoralis) and Western Flower Thrips (Frankliniella occidentalis). Implications: Although the original hypothesis that pyramiding these two trasgenes could improve drought tolerance was not supported, the unexpected positive impact on herbivore deterring, as well as the changes in dynamics of JA biosynthesis in response to wounding and the profound changes in expression of wound response genes calls for deciphering the exact linolenic acid derived signaling molecule mediating this response. This will further facilitate breeding for herbivore pest and mechanical stress tolerance based on this pathway.
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Fromm, Hillel, Paul Michael Hasegawa, and Aaron Fait. Calcium-regulated Transcription Factors Mediating Carbon Metabolism in Response to Drought. United States Department of Agriculture, 2013. http://dx.doi.org/10.32747/2013.7699847.bard.

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Original objectives: The long-term goal of the proposed research is to elucidate the transcription factors, genes and metabolic networks involved in carbon metabolism and partitioning in response to water deficit. The proposed research focuses on the GTLcalcium/calmodulinbindingTFs and the gene and metabolic networks modulated by these TFs in Arabidopsis thaliana. The specific objectives are as follows. Objective-1 (USA): Physiological analyses of GTL1 loss- and gain-of-function plants under water sufficient and drought stress conditions Objective 2 (USA / Israel-TAU): Characterizion of GTL target genes and bioinformatic analysis of data to eulcidate gene-network topology. Objective-3 (Israel-TAU): Regulation of GTLmediated transcription by Ca²⁺/calmodulin: mechanism and biological significance. Objective-4 (Israel-BGU): Metabolic networks and carbon partitioning in response to drought. Additional direction: In the course of the project we added another direction, which was reported in the 2nd annual report, to elucidate genes controlling drought avoidance. The TAU team has isolated a few unhydrotropic (hyd) mutants and are in the process of mapping these mutations (of hyd13 and hyd15; see last year's report for a description of these mutants under salt stress) in the Arabidopsis genome by map-based cloning and deep sequencing. For this purpose, each hyd mutant was crossed with a wild type plant of the Landsberg ecotype, and at the F2 stage, 500-700 seedlings showing the unhydrotropic phenotype were collected separately and pooled DNA samples were subkected to the Illumina deep sequencing technology. Bioinformatics were used to identify the exact genomic positions of the mutations (based on a comparison of the genomic sequences of the two Arabidopsis thaliana ecotypes (Columbia and Landsberg). Background: To feed the 9 billion people or more, expected to live on Earth by the mid 21st century, the production of high-quality food must increase substantially. Based on a 2009 Declaration of the World Summit on Food Security, a target of 70% more global food production by the year 2050 was marked, an unprecedented food-production growth rate. Importantly, due to the larger areas of low-yielding land globally, low-yielding environments offer the greatest opportunity for substantial increases in global food production. Nowadays, 70% of the global available water is used by agriculture, and 40% of the world food is produced from irrigated soils. Therefore, much needs to be done towards improving the efficiency of water use by plants, accompanied by increased crop yield production under water-limiting conditions. Major conclusions, solutions and achievements: We established that AtGTL1 (Arabidopsis thaliana GT-2 LIKE1) is a focal determinant in water deficit (drought) signaling and tolerance, and water use efficiency (WUE). The GTL1 transcription factor is an upstream regulator of stomatal development as a transrepressor of AtSDD1, which encodes a subtilisin protease that activates a MAP kinase pathway that negatively regulates stomatal lineage and density. GTL1 binds to the core GT3 cis-element in the SDD1 promoter and transrepresses its expression under water-sufficient conditions. GTL1 loss-of-function mutants have reduced stomatal number and transpiration, and enhanced drought tolerance and WUE. In this case, higher WUE under water sufficient conditions occurs without reduction in absolute biomass accumulation or carbon assimilation, indicating that gtl1-mediated effects on stomatal conductance and transpiration do not substantially affect CO₂ uptake. These results are proof-of-concept that fine-tuned regulation of stomatal density can result in drought tolerance and higher WUE with maintenance of yield stability. Implications: Accomplishments during the IS-4243-09R project provide unique tools for continued discovery research to enhance plant drought tolerance and WUE.
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8

Schuster, Gadi, and David Stern. Integrated Studies of Chloroplast Ribonucleases. United States Department of Agriculture, 2011. http://dx.doi.org/10.32747/2011.7697125.bard.

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Gene regulation at the RNA level encompasses multiple mechanisms in prokaryotes and eukaryotes, including splicing, editing, endo- and exonucleolytic cleavage, and various phenomena related to small or interfering RNAs. Ribonucleases are key players in nearly all of these post-transcriptional mechanisms, as the catalytic agents. This proposal continued BARD-funded research into ribonuclease activities in the chloroplast, where RNase mutation or deficiency can cause metabolic defects and is often associated with plant chlorosis, embryo or seedling lethality, and/or failure to tolerate nutrient stress. The first objective of this proposal was to examined a series of point mutations in the PNPase enzyme of Arabidopsis both in vivo and in vitro. This goal is related to structure-function analysis of an enzyme whose importance in many cellular processes in prokaryotes and eukaryotes has only begun to be uncovered. PNPase substrates are mostly generated by endonucleolytic cleavages for which the catalytic enzymes remain poorly described. The second objective of the proposal was to examine two candidate enzymes, RNase E and RNase J. RNase E is well-described in bacteria but its function in plants was still unknown. We hypothesized it catalyzes endonucleolytic cleavages in both RNA maturation and decay. RNase J was recently discovered in bacteria but like RNase E, its function in plants had yet to be explored. The results of this work are described in the scientific manuscripts attached to this report. We have completed the first objective of characterizing in detail TILLING mutants of PNPase Arabidopsis plants and in parallel introducing the same amino acids changes in the protein and characterize the properties of the modified proteins in vitro. This study defined the roles for both RNase PH core domains in polyadenylation, RNA 3’-end maturation and intron degradation. The results are described in the collaborative scientific manuscript (Germain et al 2011). The second part of the project aimed at the characterization of the two endoribonucleases, RNase E and RNase J, also in this case, in vivo and in vitro. Our results described the limited role of RNase E as compared to the pronounced one of RNase J in the elimination of antisense transcripts in the chloroplast (Schein et al 2008; Sharwood et al 2011). In addition, we characterized polyadenylation in the chloroplast of the green alga Chlamydomonas reinhardtii, and in Arabidopsis (Zimmer et al 2009). Our long term collaboration enabling in vivo and in vitro analysis, capturing the expertise of the two collaborating laboratories, has resulted in a biologically significant correlation of biochemical and in planta results for conserved and indispensable ribonucleases. These new insights into chloroplast gene regulation will ultimately support plant improvement for agriculture.
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9

Pell, Eva J., Sarah M. Assmann, Amnon Schwartz, and Hava Steinberger. Ozone Altered Stomatal/Guard Cell Function: Whole Plant and Single Cell Analysis. United States Department of Agriculture, 2000. http://dx.doi.org/10.32747/2000.7573082.bard.

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Original objectives (revisions from original proposal are highlighted) 1. Elucidate the direct effects O3 and H2O2 on guard cell function, utilizing assays of stomatal response in isolated epidermal peels and whole cell gas exchange. 2. Determine the mechanistic basis of O3 and H2O2 effects on the plasma membrane through application of the electrophysiological technique of patch clamping to isolated guard cells. 3. Determine the relative sensitivity of Israeli cultivars of economically important crops to O3 and determine whether differential leaf conductance responses to O3 can explain relative sensitivity to the air pollutant: transfer of technological expertise to Israel. Background to the topic For a long time O3 has been known to reduce gas exchange in plants; it has however been unclear if O3 can affect the stomatal complex directly. Ion channels are essential in stomatal regulation, but O3 has never before been shown to affect these directly. Major conclusions, solution, achievements 1. Ozone inhibits light-induced stomatal opening in epidermal peels isolated from Vicia faba, Arabidopsis thaliana and Nicotiana tabacum in V. faba plants this leads to reduced assimilation without a direct effect on the photosynthetic apparatus. Stomatal opening is more sensitive to O3 than stomatal closure. 2. Ozone causes inhibition of inward K+ channels (involved in stomatal opening) while no detectable effect is observed o the outward K+ channels (stomatal closure). 3. Hydrogen peroxide inhibits stomatal opening and induces stomatal closure in epidermal peels isolated from Vicia faba. 4. Hydrogen peroxide enhances stomatal closure by increasing K+ efflux from guard cells via outward rectifying K+ channels. 5. Based on epidermal peel experiments we have indirectly shown that Ca2+ may play a role in the guard cell response to O3. However, direct measurement of the guard cell [Ca2+]cyt did not show a response to O3. 6. Three Israeli cultivars of zucchini, Clarita, Yarden and Bareqet, were shown to be relatively sensitive to O3 (0.12 ml1-1 ). 7. Two environmentally important Israeli pine species are adversely affected by O3, even at 0.050 ml1-1 , a level frequently exceeded under local tropospheric conditions. P. brutia may be better equipped than P. halepensis to tolerate O3 stress. 8. Ozone directly affects pigment biosynthesis in pine seedlings, as well as the metabolism of O5 precursors, thus affecting the allocation of resources among various metabolic pathways. 9. Ozone induces activity of antioxidant enzymes, and of ascorbate content i the mesophyll and epidermis cells of Commelina communis L. Implications, both scientific and agricultural We have improved the understanding of how O3 and H2O2 do affect guard cell and stomatal function. We have shown that economical important Israeli species like zucchini and pine are relatively sensitive to O3.
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10

Sanders, Suzanne, and Jessica Kirschbaum. Forest health monitoring at Mississippi National River and Recreation Area: 2022 field season. National Park Service, 2023. http://dx.doi.org/10.36967/2301407.

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The Mississippi National River and Recreation area (MISS), situated along a 116 km stretch of the Mississippi River through the Minneapolis and St. Paul urban corridor, encompasses ~21,800 ha of public and private land. In 2022, the Great Lakes Inventory and Monitoring Network (GLKN) resampled permanent forest monitoring sites in the park, marking the second assessment of these sites, which were established and initially sampled in 2011. The goal of this long-term monitoring project is to provides managers with routine updates on which to base management decisions; these data can also be used to tease apart impacts and elucidate causal agents when novel problems or situations arise. We initiated a comprehensive forest monitoring program at MISS in 2011, establishing 33 sites at that time. High water levels during our sampling window that year precluded sampling on many of our planned sites while on others, water levels had only recently subsided. Here, the full complement of herbs had not yet emerged. In 2022, we resampled existing sites and established additional locations, bringing the total to 50. Sampled and derived metrics included trees (density and basal area of live trees, seedlings, and snags (i.e., standing dead trees)), understory (herb and shrub frequency), browse (bite marks on woody species and presence and height of herbaceous species), and taxa richness. We classified sites into four broad forest types using the newer (2022) dataset, resulting in two upland types (upland rich, upland disturbed) and two floodplain types (box elder-dominated and silver maple-dominated). Because of sampling difficulties in 2011, we are only comparing tree, sapling, and snag data between years. At upland rich sites, overall tree (? 2.5 cm diameter at breast height [DBH]) density declined 22%, while that for just the small sapling component (? 2.5 cm, &lt; 5 cm DBH) fell 41%. Species experiencing notable losses include basswood (Tilia americana L.), elm (Ulmus L.), bitternut hickory (Carya cordiformis (Wangenh.) K. Koch), and red oak (Quercus rubra L.). All three resampled sites are located in Spring Lake Park Reserve and subjected to high white-tailed deer (Odocoileus virginianus Zimm.) browse pressure. We sampled seven sites in upland disturbed forests, where overall tree density fell 17% from 778 ? 215 trees/ha to 648 ? 72 trees/ha, largely due to declines in elm, ash (Fraxinus sp. L.), and hackberry (Celtis occidentalis L.). While changes in black cherry (Prunus serotina Ehrh.) mirrored this pattern in diameter classes above 5 cm, density of saplings increased 12-fold, largely due to a swamping effect from one site, possibly in response to buckthorn (Rhamnus cathartica L.) removal. In the nine box elder-dominated sites, overall tree density declined from 635 ? 47 in 2011 to 500 ? 58 trees/ha in 2022, mainly reflecting changes in box elder (Acer negundo L.), elm, and silver maple (Acer saccharinum L.). In these sites, density of large (? 30 cm DBH) snags increased from 2.5 ? 1.6 to 11.1 ? 4.4 snags/ha. In silver maple-dominated floodplain forests, tree density in the 12 sites fell from 421 ? 63 to 291 ? 23 trees/ha, with declines observed in all five dominant species. Sapling density was low in these sites, falling from 62.6 ? 36 in 2011 to 23.6 ? 11 saplings/ha in 2022. Our observations likely reflect both deer browse and alteration of the flow regime by river impoundment. At upland sites, deer browse is impeding regeneration of all major upland species: red oak, bitternut hickory, basswood, and elm. While browse is also occurring in floodplain sites, prolonged inundation may play a larger role in regeneration failure here. Saplings of silver maple, box elder, cottonwood, elm, and hackberry all have some degree of susceptibility to inundation, ranging from moderate tolerance to completely intolerant. The Mississippi River experienced flooding in 2014, 2017, and again in 2019 when flood stage was exceeded for a record number of days in St. Paul. Sapling decline at floodplain sites is likely a direct result of this. Forest management within the park should focus both on invasive species control and floodplain reforestation. Several sites with heavy invasive weed species are in areas where leveraging local volunteers for removal projects may be possible. Floodplain reforestation requires a dual approach of research and active management. Research is needed to determine preferred propagule types and planting stock, as well as the most effective ways to control invasives, especially reed canarygrass (Phalaris arundinacea L.). Active floodplain reforestation can alleviate many of the issues we found here, although this is expensive, limited in scope, and carries with it a great deal of uncertainty. Nonetheless, projects undertaken at a small scale can provide lessons to managers, based on which aspects were successful and which were not. Many of the park forests at MISS are nearing an inflection point and are at risk of becoming irreversibly altered if countermeasures are not undertaken in the near future. At this point, steps taken to promote ecosystem integrity are likely to be less costly and more effective than those which may be needed after further ecosystem decline. The river system through the Twin Cities metro area provides numerous services, both ecological and otherwise. As the need to act is becoming a pressing issue, it is incumbent on land managers to recognize this, and address it.
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