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Journal articles on the topic 'Seedling formation'
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1
Herr, DG, LC Duchesne, R. Tellier, RS Mcalpine, and RL Peterson. "Effect of Prescribed Burning on the Ectomycorrhizal Infectivity of a Forest Soil." International Journal of Wildland Fire 4, no. 2 (1994): 95. http://dx.doi.org/10.1071/wf9940095.
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Ectomycorrhizae formation, seedling health index, and seedling survival were assessed for two-year-old nursery-grown seedlings of Pinus resinosa and Pinus strobus two months after planting in clear-cuts that had received prescribed burning under different fire intensities. Controls consisted of seedlings planted in unburned clear-cuts. Fire intensity positively correlated with percent ectomycorrhizal roots for P. strobus but not for P. resinosa. Seedling health index and survival were highest in burned-over sites as compared to control sites for both pine species. Fire intensity correlated with seedling health index for P. strobus but not for P. resinosa. Fire intensity correlated with seedling survival for both species. Colonization of seedlings by ectomycorrhizal fungi did not correlate with seedling health index or seedling survival. P. resinosa seedlings planted in burned-over sites had a smaller number of lateral roots per unit length primary/secondary roots compared to seedlings planted in control plots.
2
Amador, Talita Silveira, and Claudio José Barbedo. "Germination inhibits the growth of new roots and seedlings in Eugenia uniflora and Eugenia brasiliensis." Journal of Seed Science 37, no. 3 (2015): 241–47. http://dx.doi.org/10.1590/2317-1545v37n3150595.
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Abstract:Seeds of Eugenia species can produce new roots and whole plants even when much of its reserves is removed. However, new roots and seedlings rarely are formed spontaneously, and after cutting, each seed fragment usually produces only one new seedling, suggesting some control of the formation of several seedlings. It is possible, therefore, that germination leads to the production of inhibitory substances avoiding the development of new embryonic tissues. In the present work we have analyzed the potential of germinating seeds of Eugenia uniflora and Eugenia brasiliensisto inhibit new roots and seedling growth. Seeds were germinated after totally or partially fractionated. This last one was also totally fractionated after the development of a seedling, and the halves were also germinated. The results showed that the germination of the E. uniflora and E. brasiliensis seeds have inhibited the formation of new roots and seedlings.
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Andrade, Gisiane Camargo de, Cileide Maria Medeiros Coelho, and Matheus Santin Padilha. "Seed reserves reduction rate and reserves mobilization to the seedling explain the vigour of maize seeds." Journal of Seed Science 41, no. 4 (2019): 488–97. http://dx.doi.org/10.1590/2317-1545v41n4227354.
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Abstract: Understanding how the seed reserve dynamics occurs during germination and seedling formation is determinant for advancements on seed technology. The aims of this study were: to verify which accelerated ageing temperature is the most effective to separate the vigour levels of maize seeds and to evaluate the reserves dynamics during germination and seedling formation process. Seven maize cultivars were submitted to the germination rate, accelerated ageing, thousand seed weight, total seedling length, shoot and root length, dry matter of seed and seedling, remaining dry matter in the endosperm, seed reserves reduction rate, conversion efficiency of reserves, reserves mobilization rate to the seedling and energy expenditure using the completely randomized statistical design. The reserves dynamics and seedling formation depends on the genotype and the initial seed vigour. Accelerated ageing at 45 °C for 72 hours is the most efficient combination to segregate vigour levels. Genotypes with higher seed reserve utilisation efficiency have higher vigour, producing seedlings with higher dry matter, higher total, shoot and root length, regardless of seed weight. The two rates evaluated prompt us to conclude that they explain the maize seed vigour and can be used in quality control programs to select high physiological quality cultivars.
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Azad, Md Salim, and Md Mehedi Hasan Sumon. "Species Specific Responses to Age on Nodule Formation, Seedling Growth, and Biomass Production of Acacia auriculiformis at Nursery Stage." Journal of Botany 2016 (August 16, 2016): 1–8. http://dx.doi.org/10.1155/2016/6960783.
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Nodulation responses of leguminous trees are very important for intercropping to reduce reliance on artificial nitrogen input through nitrogen fixation in agroforestry system. This study was carried out to evaluate the status of nodulation (i.e., the number of nodules and their shape and size) in root and biomass production of plant growth parameters (i.e., number of leaves, shoot height, root biomass, and shoot biomass) of A. auriculiformis seedlings. The assessment was conducted 60 days after seed germination. The study revealed significant differences in nodule number per seedling, leaf number per seedling, shoot height, and biomass accumulation (both green and oven dry weight) with seedling age (p<0.05). The study also revealed significant correlation among the variables of nodulation responses and biomass production. The results obtained using principal component analysis (PCA) justified correlation matrix of nodulation responses and biomass production of this species. The PCA showed that root biomass per seedling, leaf number per seedling, nodule number per seedling, shoot height, age of seedling, and shoot biomass per seedling were clustered with PC1 (with an eigenvalue of 5.59) and root shoot ratios were clustered with PC2 (with an eigenvalue of 1.82). Our study justified that shoot height may be an important determinant of nodule formation of A. auriculiformis.
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Gagnon, J., C. G. Langlois, D. Bouchard, and F. Le Tacon. "Growth and ectomycorrhizal formation of container-grown Douglas-fir seedlings inoculated with Laccariabicolor under four levels of nitrogen fertilization." Canadian Journal of Forest Research 25, no. 12 (1995): 1953–61. http://dx.doi.org/10.1139/x95-210.
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Container-grown Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings were inoculated at the time of sowing with a Laccariabicolor (Maire) Orton mycelial suspension produced in a fermentor. They were grown in a peat moss–vermiculite substrate under four levels of N fertilization (7.2, 14.4, 21.6, and 28.7 mg/seedling per season (N1, N2, N3, and N4, respectively)) to determine the N level suitable for both ectomycorrhizal development and seedling growth. After 18 weeks in the greenhouse, seedlings inoculated with L. bicolor had 44%, 32%, 44%, and 5% of their short roots mycorrhizal when fertilized with N1, N2, N3, and N4, respectively. Only when they were fertilized with N4 did the L. bicolor seedlings have significantly greater shoot height than the controls. For the other growth parameters, they were not significantly different from control seedlings for any of the N levels. After 18 weeks, regardless of the level of N, seedlings inoculated with L. bicolor had significantly lower N concentrations (%) and contents (mg/seedling) than the uninoculated ones. Consequently, for the same production of biomass, the mycorrhizal seedlings had taken up less N than the nonmycorrhizal ones. The efficiency of applied N, expressed in terms of produced biomass, decreased when the N fertilization increased; mycorrhizal and nonmycorrhizal seedlings did not tend to be different. The efficiency of the absorbed N also decreased with the level of applied N, but less rapidly, and tended to be greater for the mycorrhizal seedlings than for the nonmycorrhizal ones. Therefore, the mycorrhizal infection improved the utilization of the absorbed N. N3 was the best of the four N levels used, since it was the only one that maximized both the ectomycorrhizal formation and the growth of the seedlings. In other words, a total seedling N concentration of 1.6% and a substrate fertility of 52 ppm N are appropriate to optimize both the ectomycorrhizal development and the growth of Douglas-fir seedlings.
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Torres-Ruiz, R. A., and G. Jurgens. "Mutations in the FASS gene uncouple pattern formation and morphogenesis in Arabidopsis development." Development 120, no. 10 (1994): 2967–78. http://dx.doi.org/10.1242/dev.120.10.2967.
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The pattern of cell division is very regular in Arabidopsis embryogenesis, enabling seedling structures to be traced back to groups of cells in the early embryo. Recessive mutations in the FASS gene alter the pattern of cell division from the zygote, without interfering with embryonic pattern formation: although no primordia of seedling structures can be recognised by morphological criteria at the early-heart stage, all elements of the body pattern are differentiated in the seedling. fass seedlings are strongly compressed in the apical-basal axis and enlarged circumferentially, notably in the hypocotyl. Depending on the width of the hypocotyl, fass seedlings may have up to three supernumerary cotyledons. fass mutants can develop into tiny adult plants with all parts, including floral organs, strongly compressed in their longitudinal axis. At the cellular level, fass mutations affect cell elongation and orientation of cell walls but do not interfere with cell polarity as evidenced by the unequal division of the zygote. The results suggest that the FASS gene is required for morphogenesis, i.e., oriented cell divisions and position-dependent cell shape changes generating body shape, but not for cell polarity which seems essential for pattern formation.
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Salles, Josiane S., Alexandre H. F. de Lima, Edilson Costa, et al. "Substrates and Protected Environments in the Formation of Mouriri elliptica Mart Seedlings." Journal of Agricultural Science 11, no. 6 (2019): 281. http://dx.doi.org/10.5539/jas.v11n6p281.
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The successful establishment of a forest restoration program depends of the seedling quality, and the choice of substrate and growing environment plays a significant role in the production of high-quality seedlings. A study was conducted to evaluate the production of croada seedlings (Mouriri elliptica Mart.) grown in thirteen substrate combinations and subjected to two production nurseries constructed with black shading screen (Sombrite&reg;) and aluminized thermal-reflective screen (Aluminet&reg;). The substrates were prepared from different proportions of bovine manure, soil, vermiculite, and sand. In each protected environment, the thirteen different substrate compositions were arranged in a completely randomized design with five replicates of the five seedlings each. Because there was no replication of the cultivation environments, the joint analysis was carried out, allowing the comparison of the environments in the factorial scheme 2 &times; 13 (two environments &times; thirteen substrates). Growth and quality of seedlings were measured at 188 days. Seedling production environment has no effect on the germination and emergence process of the seedlings, but the growth and quality of the seedlings can be improved when grown in the nursery with black shading screen. Substrates containing low proportion of bovine manure (from 10 to 30%) and high proportion of vermiculite (from 30 to 40%) resulted in high-quality croada seedlings.
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Schroeder, Kenneth R., and Dennis P. Stimart. "Adventitious Shoot Formation on Excised Hypocotyls of Antirrhinum majus L. (Snapdragon) In Vitro." HortScience 34, no. 4 (1999): 736–39. http://dx.doi.org/10.21273/hortsci.34.4.736.
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Hypocotyls from Antirrhinum majus L. were excised at 2 weeks of age from seedlings grown under a 16-hour photoperiod or continuous darkness. Explants were cultured on modified Murashige-Skoog (MS) medium containing 0, 0.44, 2.22, 4.44, 8.88, or 44.4 μm BA to investigate adventitious shoot formation. Excised hypocotyls from eight commercial cultivars, three inbred lines, and an F1 hybrid between two of the inbreds were cultured on MS medium containing 2.22 μm BA to assess genotypic effects on adventitious shoot formation. The influence of seedling age was assessed by excising hypocotyls from seedlings at 6, 10, 14, 18, 22, 26, or 30 days. Optimal conditions for adventitious shoot formation on excised hypocotyls included: seedling growth in a lighted environment, use of hypocotyls from 10-day-old seedlings, and culture on medium containing 2.22 μm BA for 3 weeks. Under these conditions, up to a 5-fold improvement in number of shoots per hypocotyl over previous studies was achieved. Adventitious shoot formation was genotype-dependent and appeared to be a dominant trait. Chemical name used: N6-benzyladenine (BA).
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Oster, U., and I. Blos. "The Greening Process in Cress Seedlings. III. Age-Dependent Changes in the Capacity of the Tetrapyrrole Pathway." Zeitschrift für Naturforschung C 46, no. 11-12 (1991): 1052–58. http://dx.doi.org/10.1515/znc-1991-11-1220.
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Accumulation of protochlorophyllide (Pchlide) was determined after incubation of etiolated seedlings of garden cress (Lcpidium sativum L.) with exogenous 5-aminolevulinate for 24 h. Young seedlings (start of incubation 0-12 h after imbibition) accumulated only moderate amounts (<0.2 nmol per seedling) of Pchlide. Maximum capacity of Pchlide accumulation (ca. 14 nmol per seedling) was reached at 30-36 h after imbibition. At 60-72 h after imbibition, the capacity of Pchlide formation from exogenous ALA was only 0.2-0.3 nmol per seedling. Uptake of ALA via roots was high in young and old seedlings. The carotenoid content and pattern did not change by ALA incubation. Precursors of Pchlide were also accumulated by ALA treatment. Predominant products were protoporphyrin and magnesium protoporphyrin (MgP) in 30 h old seedlings but magnesium protoporphyrin monomethylester (MgPMe) in 72 h old seedlings. The previously described interaction of Pchlide precursors with cab gene expression cannot be correlated with a single porphyrin. A possible correlation with the ratio MgPMe: MgP is discussed.
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VAN DER MEER, PETER J., FRANK J. STERCK, and FRANS BONGERS. "Tree seedling performance in canopy gaps in a tropical rain forest at Nouragues, French Guiana." Journal of Tropical Ecology 14, no. 2 (1998): 119–37. http://dx.doi.org/10.1017/s026646749800011x.
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The effect of natural canopy gaps on the performance of naturally occurring tree seedling populations was studied in a tropical rain forest in French Guiana. This was done at two levels of scale. Firstly, on a 20 m × 250 m forest transect intersecting four canopy gaps, it was investigated how patterns of recruitment, growth and survival of seedlings of Cecropia obtusa, Dicorynia guianensis and Pourouma bicolor differed between canopy gaps and closed forest. Secondly, for one large natural canopy gap, performance of seedling cohorts established before (‘pre-gap’ cohorts) and after (‘post-gap’ cohorts) gap formation was studied in relation to environmental heterogeneity. The direct site factor (DSF) was used as an indicator of light availability in the gap zone. Cecropia specialised in large gaps, and also in specific sites within the large gap: seedling performance was increased by light, and by dead wood. Pourouma mainly germinated under closed forest conditions, where it can survive for a long period until a canopy gap is formed nearby. Pourouma seedlings adjusted well to the new gap environment but they did not specialise in specific places within the gap. Seedling location of Pourouma seedlings was mainly determined by accidental positioning before gap formation. Dicorynia was able to germinate both in gaps and under closed forest conditions. Although the number of gaps studied in this study was low, the results show that seedling establishment, early growth and survival of the three tree species were affected by canopy gaps and by the environmental heterogeneity within a large gap.
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Faria, Tatiane Aparecida Curim, Thayla Morandi Ridolfi de Carvalho Curi, Tiago Lima do Espírito Santo, et al. "Substrates and cultivation environments in the production of seedlings of Genipa americana L. (Rubiaceae) seedlings." Research, Society and Development 9, no. 10 (2020): e5759107920. http://dx.doi.org/10.33448/rsd-v9i10.7920.
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This study aimed to evaluate genipap seedling formation in different protected environments using different substrates. Five protected cultivation environments (E) were used: E1 - greenhouse without aluminized shade cover under polyethylene film; E2 - greenhouse with aluminized shade cover under polyethylene film; E3 - screened with black shade cover; E4 - screened with aluminized shade cover; and E5 - nursery covered with bacuri coconut straw. In each protected cultivation environment, substrates containing different percentages of earthworm humus (H), vermiculite (V), bovine manure (M) and shredded cassava stems (C) were tested. Seedlings emerged best in environments E2, E3 and E4. Mixtures ¾ H + ¼ V and ¾ H + ¼ C favored growth and yielded high quality seedlings. Environments E3 and E4 provided superior growth, with better- quality and high-quality seedlings. Environments E1 and E5 did not provide adequate seedling growth. Therefore, were not recommended for genipap seedling production using the substrates tested.
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Bastide, Paul Y. de la, and Bryce Kendrick. "The in vitro effects of benomyl on disease tolerance, ectomycorrhiza formation, and growth of white pine (Pinus strobus) seedlings." Canadian Journal of Botany 68, no. 2 (1990): 444–48. http://dx.doi.org/10.1139/b90-057.
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The influence of benomyl (methyl 1-(butylcarbamoyl)-2-benzimidazolecarbamate) on disease tolerance, growth, and mycorrhization of aseptically grown white pine (Pinus strobus) seedlings was assayed using the growth pouch technique. Six-day-old seedlings were inoculated concurrently with plugs of a pathogenic fungus Mycelium radicis atrovirens and the ectomycorrhizal fungus Laccaria bicolor. Treatment with benomyl (100 ppm) reduced the pathogenic effects of M. radicis atrovirens, enhanced mycorrhization, and improved both shoot and overall seedling growth. The fungicidal activity of benomyl and improved mycorrhization by L. bicolor may both have influenced the pathogenicity of M. radicis atrovirens. A reduction in fungal competition within the seedling rhizosphere may improve the access of L. bicolor to potential colonization sites.
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Pitt, Michael W., and John N. A. Lott. "Large globoid particles in the cotyledons of Cucurbita maxima seedlings." Canadian Journal of Botany 74, no. 7 (1996): 1186–89. http://dx.doi.org/10.1139/b96-141.
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Light microscopy and transmission electron microscopy revealed the location of previously identified large protein body globoids within the cotyledons of Cucurbita maxima seedlings. Large globoids formed in the three cell layers of the spongy mesophyll above the lower epidermis. The large globoids share morphological similarities to typical globoids by being spherical and naturally electron dense, but they were approximately four times the size of regular globoids, ranging from 4 to 8 μm in diameter. The formation of the large globoid particles occurred around 3 days of seedling growth and likely resulted from fusion of a number of typically sized globoids. This method of formation was supported by the appearance of clusters of regular globoids prior to the formation of the unusually large globoids. The volume of a large globoid was less than the combined volume of all the typical-sized globoids found within a mesophyll cell earlier in seedling growth. Keywords: large globoids, cotyledon, Cucurbita maxima, mesophyll, seedling, protein bodies.
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Dumroese, R. Kasten, Douglass F. Jacobs, and Anthony S. Davis. "Inoculating Acacia koa with Bradyrhizobium and Applying Fertilizer in the Nursery: Effects on Nodule Formation and Seedling Growth." HortScience 44, no. 2 (2009): 443–46. http://dx.doi.org/10.21273/hortsci.44.2.443.
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Restoration of Acacia koa A. Gray (koa) forests on degraded sites in Hawaii is important for conservation of rare, endemic plants and animals and is often accomplished by planting nursery-grown seedlings. To be successful after outplanting, koa seedlings must access sufficient nutrients from the soil and outcompete other vegetation. Forming symbiotic associations with nitrogen-fixing microorganisms may help alleviate inherent nutrient deficiencies found on volcanic sites, but interactions between inoculation and fertilization during production of koa seedlings are not well studied. Under operational nursery conditions, we fertilized koa seedlings at six controlled-release fertilizer (CRF) rates (ranging from 0 to 11.9 kg·m−3 Osmocote Plus 15N–9P–12K), which were also either inoculated with a locally collected source of nitrogen-fixing Bradyrhizobium spp. or not. Fertilized seedlings were significantly larger than the control; on average, fertilized seedlings were 300% taller and had 180%, 700%, and 350% more root-collar diameter, shoot biomass, and root biomass, respectively. Nitrogen (N) concentration was 23% to 119% greater in fertilized seedlings than nonfertilized seedlings. Inoculation with Bradyrhizobium had no significant affect on seedling characteristics except for root N concentration, which was 8% higher for inoculated seedlings. Fertilizer rate and inoculation interacted to significantly affect nodule number and nodule biomass/seedling. With inoculation, we observed an increase in nodule number (16.5 to 25.5) and biomass (5.8 mg to 11.7 mg) with fertilizer rate up to 4.7 kg·m−3 but a decline to nearly zero at the highest rates. Without inoculation, nodule formation was scarce (3.2 nodules/seedling or less) and only observed when CRF was 2.3 kg·m−3 or less. Our results suggest that high rates of fertilization and successful nodulation are not mutually exclusive nursery practices. Concurrent use of fertilization and inoculation in the nursery may provide opportunity to produce larger seedlings that have high potential to reduce the time needed to achieve canopy closure and thereby help achieve restoration objectives.
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Luqui, Laís De Lima, Josiane Souza Salles, Edilson Costa, et al. "SEEDLINGS PRODUCTION AND FRUIT YIELD OF CUCUMBER ON DIFFERENT ORGANIC SUBSTRATES." JOURNAL OF NEOTROPICAL AGRICULTURE 6, no. 4 (2019): 1–7. http://dx.doi.org/10.32404/rean.v6i4.3544.
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Demand for agricultural products with zero or reduced amounts of agrochemicals leads to increasingly healthy production alternatives. Thus, seedling formation and fruit yield of three cucumber cultivars were evaluated on different organic substrates in a protected environment. Marketer, Caipira and Verde Comprido cultivars were grown on five substrates: 100% cassava stems + 0% cattle manure; 75% cassava stems + 25% cattle manure; 50% cassava stems + 50% cattle manure; 25% cassava stems + 75% cattle manure and 0% cassava stems + 100% cattle manure. A completely randomized design in a 5 x 3 factorial scheme (5 substrates X 3 cultivars) was used, with six replications of four seedlings in the seedling formation phase and five replications of two plants in the fruit production phase. The seedlings were produced in trays with 72 cells, and fruit production was conducted in 13-liter pots. There was a little influence of the substrates on the emergence of cucumber cultivars: the substrates with 75 and 100% of cattle manure provided the best conditions for seedling formation, as well as the highest yield and the largest amount of fruits. On the best substrates, the cultivar Caipira had fruits with higher mass and larger average fruit diameter, but in smaller numbers.
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Gagnon, J., C. G. Langlois, and J. Garbaye. "Growth and ectomycorrhiza formation of container-grown red oak seedlings as a function of nitrogen fertilization and inoculum type of Laccariabicolor." Canadian Journal of Forest Research 21, no. 7 (1991): 966–73. http://dx.doi.org/10.1139/x91-134.
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Containerized red oak (Quercusrubra L.) seedlings were inoculated at the time of sowing with Laccariabicolor (Maire) Orton using two methods to compare the efficiency of two inoculum types: a mycelial suspension (Ecot-Sol®101) produced by Rhizotec Laboratories Inc. and calcium alginate beads containing this mycelial suspension. Red oak seedlings were also grown for 19 weeks in a peat moss – vermiculite substrate under three levels of N fertilization (100, 120, and 140 mg/seedling per season) to determine the N level that maximizes the ectomycorrhizae formation and growth of seedlings. After 19 weeks in the greenhouse, seedlings inoculated with liquid inoculum had significantly more mycorrhizae than both those inoculated with beads and controls, regardless of the N level. For any of the N levels, liquid-inoculated seedlings had significantly lower shoot height, root-collar diameter, and dry weights (shoot, root, and total) than both those inoculated with beads and the controls, whereas there were no significant differences for any growth parameters between the bead and control treatments. For the three inoculum treatments, root and total dry weights of seedlings fertilized with 100 mg N were significantly lower than those of seedlings that received both 120 and 140 mg N, whereas shoot height, root-collar diameter, and shoot:root ratio of seedlings did not differ significantly between any of the three N levels. After 19 weeks, seedlings inoculated with liquid inoculum had significantly greater N and P concentrations (%) and contents (mg/seedling) than those inoculated with beads only at the 140 mg N level. Analyses show that seedling concentrations of 1.2% N and 0.1% P and substrate fertility of 25 ppm N and 30 ppm P would be appropriate to maintain the ectomycorrhizal association Q. rubra – L. bicolor.
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Thomson, J., U. Matthes-Sears, and R. L. Peterson. "Effects of seed provenance and mycorrhizal fungi on early seedling growth in Piceamariana." Canadian Journal of Forest Research 20, no. 11 (1990): 1739–45. http://dx.doi.org/10.1139/x90-231.
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The importance of provenance and fungal species effects on mycorrhiza formation in Piceamariana was determined. Seed was collected from two sites near Chapleau, Ontario. One provenance was collected from an upland site with sandy soil, the second from a lowland site with peaty soil. Seedlings were grown under aseptic conditions in test tubes. Two experiments were performed: in the first, seedlings were inoculated with Hebelomacylindrosporum, Laccarialaccata, or Paxillusinvolutus, whereas in the second, seedlings were inoculated with Laccariabicolor, Laccarialaccata, Laccariaproximo or noninoculated agar plugs. Counts of ectomycorrhiza and lateral root formation were analyzed for significance with two-way factorial ANOVAS. When inoculated with L. laccata, seedlings from the lowland seed source had significantly more mycorrhizal second order lateral roots than seedlings from the upland seed source. Lowland seedlings also had greater shoot dry weight and foliage length values. However, overall differences between provenances were small. In contrast, differences between fungal treatments were pronounced. Both L. laccata and L. bicolor initiated good ectomycorrhiza formation and increased seedling growth.
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Oliveira, Ademir Kleber Morbeck, and Jose Carlos Pina. "SEED GERMINATION OF Pouteria torta (MART.) RADLK. SUBESP. torta IN DIFFERENT ENVIRONMENTAL CONDITIONS." FLORESTA 50, no. 1 (2019): 923. http://dx.doi.org/10.5380/rf.v50i1.59051.
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Germination is considered a critical step in the seedling production process aiming the recovery of environments. Thus, understanding the germination behavior of native species with potential for economic use contributes to the development of the forest seed and seedling chain. Considering the limited information on the tree species Pouteria torta subesp. torta, this study aimed to evaluate its seed germination and formation of normal seedlings using different temperatures and substrates. The experiment was conducted in germination chamber in a research laboratory using two substrates (paper and vermiculite) and six temperatures (20, 25, 30, 35, 20-30 and 25-35 °C) in a completely randomized design in a 2x6 factorial arrangement. Daily evaluation was conducted to verify primary root emission, seed vigor, and seedling formation. The results indicated that the primary root protrusion process began after 20 days of testing under the best conditions, with germination time lasting longer than two months. The results obtained also showed that there was interaction between factors, with use of the vermiculite substrate and the temperatures of 35 and 25-35 °C producing the best germination rates and germination speed index, and use of the paper substrate and the temperatures of 30 and 35 °C showing the best mean germination time. Considering the analyzed variables (germination, germination speed index, and formation of normal seedlings), the temperatures of 35 and 25-35 °C and the vermiculite substrate are the most suitable for the production of Pouteria torta subesp. torta seedlings.
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Macey, D. E., and J. T. Arnott. "The effect of moderate moisture and nutrient stress on bud formation and growth of container-grown white spruce seedlings." Canadian Journal of Forest Research 16, no. 5 (1986): 949–54. http://dx.doi.org/10.1139/x86-168.
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Piceaglauca (Moench) Voss seedlings were grown in controlled environment rooms following germination with a combination of fluorescent and incandescent lamps (ratio, 1.4:1) providing 390 μmol s−1 m−2 of photosynthetically active radiation over a 24-h photoperiod. Moderate moisture and nutrient stress treatments were applied to separate seedling groups (10 weeks from germination) for a 2-week period during the initial free growth phase when mean seedling shoot length had reached 12 cm. Photoperiod was then reduced to 8 h. Both periodic moisture stress (reaching −1.72 MPa) and nutrient withdrawal (N, P, K) were effective in inducing terminal bud formation in container-grown white spruce seedlings under nonlimiting photoperiod and the number of needle primordia subsequently formed in the terminal bud under short days was significantly reduced. However, decreased needle complements in the stressed seedlings did not result in reduced shoot growth in the second growing season. Free growth following extension of the preformed shoot compensated for the reduced amount of predetermined foliage.
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Ehrhardt-Brocardo, Natalia Carolina Moraes, and Cileide Maria Medeiros Coelho. "Hydration patterns and physiologic quality of common bean seeds." Semina: Ciências Agrárias 37, no. 4 (2016): 1791. http://dx.doi.org/10.5433/1679-0359.2016v37n4p1791.
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This study aimed to investigate the relationship between the hydration pattern of landrace bean genotypes and their physiological quality. The hydration curve of eight landrace (BAFs 07, 13, 23, 42, 44, 50, 55, 81) and two commercial cultivars (IPR-88-Uirapurú and Iapar 81) genotypes was determined from seed moisture. Determination of initial physiological quality was performed by germination and vigor tests (seedling performance and accelerated aging). Characterization of the genotypes, regarding accelerated aging tests, showed that BAFs 13, 42, 55 and 81 had the highest physiological potential, whereas BAFs 07, 23, 44, 50 and the commercial cultivars had lower physiological quality. The hydration curve followed a triphasic pattern with radicle protrusion occurring between 21 and 27 hours after seed hydration. The percentage of reserves translocated to the seedling during formation showed that BAF 42 had the highest conversion efficiency compared to the smaller efficiencies of BAFs 23, 50 and Iapar 81. The seedling length test showed that BAFs 42 and 55 had the most vigorous seedlings, which was driven by the high percentage of reserves translocated to the seedling during formation. BAFs 23, 50 and the cultivar Iapar 81 showed lower reserve translocation, demonstrating that low mobilization potential leads to smaller seedlings. The hydration of bean seeds during germination was affected by physiological quality, as genotypes considered more vigorous exhibited higher hydration rates than those of the less vigorous genotypes.
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Crowley, David E., Dale M. Maronek, and James W. Hendrix. "Effect of Slow Release Fertilizers on Formation of Mycorrhizae and Growth of Container Grown Pine Seedlings." Journal of Environmental Horticulture 4, no. 3 (1986): 97–101. http://dx.doi.org/10.24266/0738-2898-4.3.97.
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Slow-release fertilizer formulations at various NPK analyses, release rates, and application rates were evaluated for their effects on seedling growth and mycorrhizal development of container-grown seedlings of Pinus echinata (Mill.) inoculated with Pisolithus tinctorius (Pers.) Coker and Couch. Fertilizer release rate and application rate affected formation of mycorrhizae. At 9.0 kg/m3 (15.0 lb/yd3), greater numbers of seedlings formed mycorrhizae and a greater portion of the root system was mycorrhizal with the 8 to 9 month release fertilizer, regardless of formulation, than with the 1 to 2 or 3 to 4 month release fertilizers. Best seedling growth and mycorrhizae formation was obtained with the 21N-3.OP-11.6K (21-7-14) 8 to 9 month release fertilizer at the 4.5 kg/m3 (7.5 lb/yd3) application rate. Because fertilizer release is temperature dependent, deleterious effects of over fertilization may be greater with higher greenhouse temperatures. The low benefits of fertilization rates higher than 4.5 kg/m3 (7.5 lb/yd3) do not warrant the risk of interference with formation of mycorrhizae.
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Alves, José Darlon Nascimento, Wendel Kaian Oliveira Moreira, Leilane Ávila Bezerra, et al. "Substrates and Irrigation Frequencies in the Development of Seedlings of Schizolobium parahyba var. amazonicum." Journal of Agricultural Science 10, no. 11 (2018): 249. http://dx.doi.org/10.5539/jas.v10n11p249.
Full textAbstract:
Knowledge on the ideal conditions for the formation of high quality seedlings is fundamental to guarantee establishment success of crops in a safe and efficient manner. Here, we evaluate the effect of different substrates and irrigation frequencies on the initial growth of parica (Schizolobium parahyba var. amazonicum) seedlings. The experiment was conducted in a greenhouse at the Federal Rural University of Amaz&ocirc;nia, Capit&atilde;o Po&ccedil;o, PA. Several variables were analyzed including seedling height, stem diameter, number of leaflets, shoot dry matter, root dry matter, total dry matter, height and stem diameter ratio, shoot dry matter ratio and root dry matter. We found significant differences in seedling development between the applied treatments, including a significant interaction between substrate type and irrigation regime on seedling height, stem diameter, the number of leaflets and plant growth indices, with the best response for proportions 75% soil + 25% bovine manure and 50% soil + 50% bovine manure. Therefore, the substrates containing organic compounds resulted in a higher quality of the seedlings, while the sand consistently presented the lowest increases in seedling production under the three experimental irrigation frequencies, and thus is not recommended as a substrate for the development of Schizolobium parahyba var. amazonicum.
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Simpson, David G. "Auxin stimulates lateral root formation of container-grown interior Douglas-fir seedlings." Canadian Journal of Forest Research 16, no. 5 (1986): 1135–39. http://dx.doi.org/10.1139/x86-199.
Full textAbstract:
The effects of 1-napthaleneacetic acid (NAA) and 3-indolebutyric acid (IBA) soil drenches on lateral root formation and growth of interior Douglas-fir (Pseudotsugamenziesii var. glauca (Beissn.) Franco) seedlings were studied. At rates between 10−3 and 10−5 M, NAA was more effective than IBA in stimulating first-order lateral root formation. Seedling age influenced the degree of NAA-induced lateral root formation. At three different nurseries the greatest number of lateral roots was produced by seedlings receiving 10−4 M (18.62 mgL−1) NAA 30 days after sowing. Shoot height and dry weight were reduced, although not at the expense of root growth in some cases.
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Delissio, Lisa J., Richard B. Primack, Pamela Hall, and H. S. Lee. "A decade of canopy-tree seedling survival and growth in two Bornean rain forests: persistence and recovery from suppression." Journal of Tropical Ecology 18, no. 5 (2002): 645–58. http://dx.doi.org/10.1017/s0266467402002420.
Full textAbstract:
The population dynamics of 8500 shade-tolerant tree seedlings of 13 tree species were followed for 10 years at rain forests in Lambir Hills National Park and Bako National Park, Malaysian Borneo. Since these dipterocarp forests have lower rates of canopy gap formation than do rain forests elsewhere, tree seedling biology was predicted to differ. Approximately 50% of seedlings present in 1986 were still alive in 1996. Seven out of thirteen had seedling populations composed predominantly of individuals that were at least 10 years old. These seedlings can undergo alternating periods of relatively rapid and slow growth. Many seedlings that grew rapidly in the first census interval survived through a period of suppression in the second census interval, and conversely many seedlings with a history of suppression had exceptionally high growth in the final census interval. Seedlings of South-East Asian forest tree species are long-lived and appear to be adapted to long periods of suppression in the understorey.
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Hung, Ling-Ling L., and Randy Molina. "Use of the ectomycorrhizal fungus Laccarialaccata in forestry. III. Effects of commercially produced inoculum on container-grown Douglas-fir and ponderosa pine seedlings." Canadian Journal of Forest Research 16, no. 4 (1986): 802–6. http://dx.doi.org/10.1139/x86-142.
Full textAbstract:
Inoculation of container-grown Douglas-fir and ponderosa pine seedlings with vegetative inoculum of Laccarialaccata (Scop.:Fr.) Berk. & Br., prepared by Sylvan Spawn Laboratory, yielded ectomycorrhizae in a research greenhouse experiment; however, in two container nurseries, ectomycorrhizae were observed only on inoculated Douglas-fir seedlings. Successfully colonized seedlings had more short roots than did the controls. The percentage of L. laccata ectomycorrhizae increased with increasing inoculation rates. Inoculation rate for best seedling growth and ectomycorrhiza formation differed between nurseries. Inoculation at an "optimal" rate resulted in quality seedlings and abundant ectomycorrhiza formation at each nursery. Inoculation of Douglas-fir with L. laccata in a commercial nursery application is feasible.
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Yuan, Hongmei, Lijuan Zhao, Wendong Guo, et al. "Exogenous Application of Phytohormones Promotes Growth and Regulates Expression of Wood Formation-Related Genes in Populus simonii × P. nigra." International Journal of Molecular Sciences 20, no. 3 (2019): 792. http://dx.doi.org/10.3390/ijms20030792.
Full textAbstract:
Although phytohormones are known to be important signal molecules involved in wood formation, their roles are still largely unclear. Here, Populus simonii × P. nigra seedlings were treated with different concentrations of exogenous phytohormones, indole-3-acetic acid (IAA), gibberellin (GA3), and brassinosteroid (BR), and the effects of phytohormones on growth were investigated. Next, 27 genes with known roles in wood formation were selected for qPCR analysis to determine tissue-specificity and timing of responses to phytohormone treatments. Compared to the control, most IAA, GA3, and BR concentrations significantly increased seedling height. Meanwhile, IAA induced significant seedling stem diameter and cellulose content increases that peaked at 3 and 30 mg·L−1, respectively. Significant increase in cellulose content was also observed in seedlings treated with 100 mg·L−1 GA3. Neither stem diameter nor cellulose content of seedlings were affected by BR treatment significantly, although slight effects were observed. Anatomical measurements demonstrated improved xylem, but not phloem, development in IAA- and BR-treated seedlings. Most gene expression patterns induced by IAA, GA3, and BR differed among tissues. Many IAA response genes were also regulated by GA3, while BR-induced transcription was weaker and slower in Populus than for IAA and GA3. These results reveal the roles played by phytohormones in plant growth and lay the foundation for exploring molecular regulatory mechanisms of wood formation in Populus.
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Amaranthus, M. P., and D. A. Perry. "Effect of soil transfer on ectomycorrhiza formation and the survival and growth of conifer seedlings on old, nonreforested clear-cuts." Canadian Journal of Forest Research 17, no. 8 (1987): 944–50. http://dx.doi.org/10.1139/x87-147.
Full textAbstract:
Small amounts (150 mL) of soil from established conifer plantations and mature forest were transferred to planting holes on three clear-cuts in southwest Oregon and northern California to enhance mycorrihiza formation. The clear-cuts, 8–27 years old and unsuccessfully reforested, included a range of environmental conditions. At Cedar Camp, a high-elevation (1720 m) southerly slope with sandy soil, transfer of plantation soils increased 1st-year Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedling survival by 50%. Notably, soil from a plantation on a previously burned clear-cut doubled mycorrhiza formation and tripled seedling basal area growth. Soil from mature forest did not improve survival and growth. Less dramatic effects owing to soil transfer were evident on other sites, which were lower in elevation and had clayey soils with greater water-holding capacity, and where woody shrubs had apparently preserved mycorrhizal fungi. At Crazy Peak (1005 m), seedling survival was uniformly good, and soil from a previously burned plantation increased Douglas-fir mycorrhiza formation. At Wood Creek (500 m), soil from a plantation on a previously unburned clear-cut increased mycorrhizal branching on sugar pine (Pinuslambertiana Dougl.) seedlings, but there was no other effect. Results suggest that adequate mycorrhiza formation is critical to seedling growth and survival on cold, droughty sites. Populations of mycorrhizal fungi, and perhaps other beneficial soil biota, decline if reforestation is delayed or other host plants are absent. These declines can be offset by soil transfer from the proper source; in this study, soil from vigorous young plantations.
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Ferreira, Sidney Alberto do Nascimento, and Daniel Felipe de Oliveira Gentil. "Seed germination at different stratification temperatures and development of Phytelephas macrocarpa Ruiz & Pavón seedlings." Journal of Seed Science 39, no. 1 (2017): 20–26. http://dx.doi.org/10.1590/2317-1545v39n1166371.
Full textAbstract:
Abstract: Phytelephas macrocarpa (ivory palm) is an Amazonian palm vulnerable to exploitation pressure, as its seeds are widely used in regional handicrafts. The aims of this study were to evaluate the effectiveness of different stratification temperatures in overcoming seed dormancy and to analyze the seedling development stages of this species. In germination under stratification, the seeds were placed in plastic bags containing moistened vermiculite, and maintained at the constant temperatures of 25, 30, 35 and 40 °C, and an alternating temperature from 26 to 40 °C. In the study about the development of seedlings, seeds were sown in vermiculite under plastic cover (growing house), and the evolution of the seedling was evaluated, from the formation of germinative button to the complete blade expansion of the first eophyll. Stratification at alternating temperatures (26 to 40 °C) helped overcoming seed dormancy. Stratification at 25 °C kept the seed viability for nine months. Germination, characterized by the formation of the germinative button took an average of 114 ± 24 days, and the seedling development until the first extended eophyll lasted 244 ± 57 days.
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Ross, Neil D., and Angela T. Moles. "The contribution of pathogenic soil microbes to ring formation in an iconic Australian arid grass, Triodia basedowii (Poaceae)." Australian Journal of Botany 69, no. 3 (2021): 113. http://dx.doi.org/10.1071/bt20122.
Full textAbstract:
Ring-forming species of spinifex grasses (Triodia spp.) are a dominant feature across much of Australia’s arid and semi-arid zone. Researchers have long been curious about the mechanisms underpinning their striking growth form. However, none of the factors investigated to date provide a convincing explanation for ring formation. Here, we asked whether an accumulation of pathogenic soil microbes might impede seedling emergence and subsequent growth in the centre of Triodia basedowii rings. We collected soil from inside and outside naturally occurring spinifex rings and compared plants grown in soil with live microbes to plants grown in sterilised soil. Consistent with our hypothesis, we found that emergence of T. basedowii seedlings was lower in live soil from inside the rings than in live soil from outside the rings. Further, seedling emergence in soil from inside the rings increased significantly in response to soil sterilisation. We found no significant difference in growth between sterile and live soils. However, this might be due to a lack of power caused by high rates of seedling mortality in all treatments. Overall, our study provides evidence for the role of soil pathogens in shaping this iconic Australian grass.
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Yao, Linling, Jialin Huang, and Shibao Zhang. "An Improved Protocol for Asymbiotic Seed Germination and Seedling Development of Paphiopedilum tigrinum." Horticulturae 7, no. 9 (2021): 298. http://dx.doi.org/10.3390/horticulturae7090298.
Full textAbstract:
Paphiopedilum tigrinum is an endangered orchid with high ornamental value. However, seed germination and seedling regeneration in P. tigrinum is very difficult in vitro. Little is known about why P. tigrinum seedlings are difficult to propagate or how to improve the seed germination and seedling rates of this species. In this study, we investigated the developmental process of P. tigrinum from asymbiotic seed germination to seedling rooting by comparing it with P. appletoniantum, a much easier species for germination and seedling formation. We found that asymbiotic seed germination in P. tigrinum is limited by severe browning of the protocorm at the seed germination stage, and protocorm rooting at the differentiation stage was also proved to be difficult. The optimal medium for seed germination of P. tigrinum was a modified Harvais (mHa) medium supplemented with 0.5 mg·L−1 kinetin (Kin), 0.1 g·L−1 activated charcoal (AC) and 100 mL·L−1 coconut water (CW). At the protocorm differentiation stage, seedlings with 1–2 leaves were obtained on a 1/4 MS medium supplemented with 1.0 mg·L−1 6-benzylaminopurin (BA), 0.3 g·L−1 AC and 50–100 mL·L−1 CW after culturing for 120 day. At the seedling subculture stage, a 1/2 MS medium supplemented with 0.5–1.5 g·L−1 AC and 100 mL·L−1 CW was better for leaf and root growth of P. tigrinum. At the rooting stage, a 1/2 MS medium supplemented with 1.0 g·L−1 AC, 0.5 g·L−1 dolomite flour, 15 g·L−1 potato homogenate and 30 g·L−1 banana homogenate was most suitable for the growth and rooting of seedlings. This study has established an effective protocol for seed germination and seedling regeneration of P. tigrinum.
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Becker, C. A., G. D. Mroz, and L. G. Fuller. "The effects of plant moisture stress on red pine (Pinusresinosa) seedling growth and establishment." Canadian Journal of Forest Research 17, no. 8 (1987): 813–20. http://dx.doi.org/10.1139/x87-129.
Full textAbstract:
Red pine (Pinusresinosa Ait.) 2-0 and 3-0 bare-root and 1-0 containerized seedlings were subjected to five different watering regimes (drying cycles). Overall, moisture stress as measured with a pressure bomb was highly correlated with seedling growth and survival. While shoot elongation during the drought period was unaffected, stressed seedlings showed pronounced decreases in cambial activity, secondary needle elongation, subsequent bud formation, root length, and number of active mycorrhizal root tips per centimetre compared with control treatments. This resulted in reduced top and root dry-matter production. Watering treatments with average seasonal internal moisture stress values in the range of −8 to −11 bar (1 bar = 100 kPa) showed no measurable reductions in seedling growth. Consistently, less internal moisture stress in the containerized seedlings indicate they are better able to avoid drought. Overall, performance of the 2-0 bare-root seedlings was superior to that of the 3-0 and containerized stock.
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Beckage, Brian, James S. Clark, Barton D. Clinton, and Bruce L. Haines. "A long-term study of tree seedling recruitment in southern Appalachian forests: the effects of canopy gaps and shrub understories." Canadian Journal of Forest Research 30, no. 10 (2000): 1617–31. http://dx.doi.org/10.1139/x00-075.
Full textAbstract:
We examined the importance of intermediate-sized gaps and a dense shrub layer on tree seedling recruitment in a southern Appalachian deciduous forest. We created 12 canopy gaps under two contrasting understory conditions: 6 gaps were dominated by the dense, shade-producing shrub, Rhododendron maximum L., while the remaining gaps were relatively open. Density of first-year and >first-year seedlings was monitored for 5 years in transects extending from adjacent undisturbed forest through the experimental gaps. We concurrently measured the understory light environment, soil moisture, litter biomass, and seed rain. Neither species diversity nor richness consistently increased following gap formation. Acer rubrum L. responded consistently to canopy gaps with increased seedling densities while most other species, including both shade-tolerant and shade-intolerant species, did not. Seedling densities were especially low and unresponsive to gap formation in areas dominated by R. maximum. Understory light levels were consistently low beneath R. maximum and did not increase with canopy gap formation. Our results suggest that dense shrub cover can neutralize recruitment opportunities in canopy gaps, that seed rain often limits recruitment in gaps, and that canopy gaps that are larger or include understory disturbance are needed to maintain diversity in these forests.
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Lombardi, Simone Pacheco, Ilene Ribeiro da Silva Passos, Maria Cristina Stolf Nogueira, and Beatriz Appezzato-da-Glória. "In vitro shoot regeneration from roots and leaf discs of Passiflora cincinnata mast." Brazilian Archives of Biology and Technology 50, no. 2 (2007): 239–47. http://dx.doi.org/10.1590/s1516-89132007000200009.
Full textAbstract:
Different concentrations of 6-benzyladenine (6-BA) were used in vitro to induce buds in three types of explants: leaf discs, root segments and the seedling itself obtained from in vitro seed germination of Passiflora cincinnata Mast. The 0.5 mg.L -1 6-BA concentration was most suitable for all the three explants, however, bud formation time and means (direct/indirect) were different for each type of explant. In seedlings used as explants, it had shoot regeneration from the primary root. Histological events leading to bud formation via meristemoids were described. The origin was indirect in leaf discs, with callus formation in subepidermal cells of the chlorophyll parenchyma layers. In root segments and in seedling roots, the buds were formed directly in the pericycle (in roots with some secondary structure) and in the vascular cambium (at the initial phase of secondary structure). Also, indirect buds originated from meristemoids which were formed around the callus.
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Falls, Robert W., Peter Toivonen, and Iain E. P. Taylor. "Chlorophyll a fluorescence and preseason seedling dimensions as indicators of wood formation rates in white spruce (Piceaglauca)." Canadian Journal of Forest Research 21, no. 7 (1991): 1106–10. http://dx.doi.org/10.1139/x91-152.
Full textAbstract:
Variable chlorophyll a fluorescence and dimensions of white spruce (Piceaglauca (Moench) Voss) seedlings were measured, and their effectiveness as noninvasive indicators of current-season wood formation rates (cambial activity) in white spruce were compared. Average fluorescence was over 300 s and was correlated with cambial activity (r2 = 0.773). Fluorescence amplitudes at M2 (maximum level) and T (terminal steady level) of the induction curve were also correlated with cambial activity (r2 = 0.542 and 0.684, respectively). Relationships between these fluorescence parameters and cambial activities were reduced in wounded seedlings and absent in geotropically stressed seedlings. Neither preseason cross-sectional stem areas nor preseason seedling heights were strongly correlated with cambial activities of untreated seedlings; however, a weak relationship between current-season leader lengths and cambial activities (r2 = 0.420) was indicated.
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Pinzón, Zuleika S., Katherine C. Ewel, and Francis E. Putz. "Gap formation and forest regeneration in a Micronesian mangrove forest." Journal of Tropical Ecology 19, no. 2 (2003): 143–53. http://dx.doi.org/10.1017/s026646740300316x.
Full textAbstract:
Gaps created by the death of one or more contiguous trees are common in mangrove forests but are poorly understood. In Kosrae, Federated States of Micronesia, where mangrove wood is harvested for local use, most natural gaps were < 50 m2, whereas most logging gaps were > 100 m2. Interior zones, where access is facilitated by roads, were the most heavily exploited. Although the forests contained 11 species, two species were primarily responsible for gap formation. Natural gaps were caused mainly by broken stems and large branches of Sonneratia alba trees, whereas logging gaps were created primarily by harvesting Rhizophora apiculata trees. Most natural gaps were formed by the fall of more than one tree or branch. Seedling densities were higher in logging gaps than in natural gaps and higher in gaps than under intact canopy. Bruguiera gymnorrhiza was the most common seedling species in gaps and under intact canopy. Relative rates of growth in height were faster in gaps than under intact canopy for R. apiculata and B. gymnorrhiza seedlings. Current harvesting practices on the island do not seem to be altering species richness, although R. apiculata may become less common as gaps are increasingly captured by B. gymnorrhiza.
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Finneseth, C. L. H., Desmond R. Layne, and R. L. Geneve. "Influence of Ontological Age on Adventitious Bud and Shoot Formation of Pawpaw [Asimina triloba (L.) Dunal] Nodal Explants." HortScience 32, no. 3 (1997): 441E—441. http://dx.doi.org/10.21273/hortsci.32.3.441e.
Full textAbstract:
Clonal propagation of pawpaw is currently limited to budding and grafting. A tissue-culture system to rapidly produce clonal material would be valuable for both production and preservation of germplasm. Forced scion wood, shoots from root cuttings, and seedlings were explant sources for ontologically mature, intermediate, and juvenile ages, respectively. Preliminary data indicated that nodal explants had more rapid adventitious shoot formation than shoot tip explants. Disinfestation protocols were developed for each explant source. Nodal explants were cultured on MS medium supplemented with 10 μM BA and 0.1 μM TDZ. Within 3 weeks, 60% of the seedling explants had expanded axillary buds, while no bud expansion was observed for explants of either the intermediate or mature sources. By 6 weeks, seedling axillary shoots had elongated and were suitable for subculture. By 8 weeks, multiple adventitious buds and shoots had formed on all seedling explants. At this same time, axillary shoots began to elongate on intermediate source explants, but mature source explants appeared to be recalcitrant. Explant exudation caused medium darkening, but, by reducing the transfer interval from 4 to 2 weeks, discoloration was minimized. Mature source explants were maintained in culture and after ≈7 months, axillary bud expansion occurred in a small percentage of these explants.
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Quoreshi, A. M., and V. R. Timmer. "Exponential fertilization increases nutrient uptake and ectomycorrhizal development of black spruce seedlings." Canadian Journal of Forest Research 28, no. 5 (1998): 674–82. http://dx.doi.org/10.1139/x98-024.
Full textAbstract:
Intensive fertilization may inhibit adequate mycorrhizal development for forest nursery stock production. Containerized black spruce (Picea mariana (Mill.) BSP) seedlings exposed to four fertilization regimes (one conventional and three exponential at 12.5, 12.5, 25, and 50 mg N/seedling, respectively) and two ectomycorrhizal inoculations (Hebeloma crustuliniforme (Bull. ex St-Amans) Quel. and Laccaria bicolor (R. Mre.) Orton) were grown from seed to assess mycorrhizal formation and nutrition of young trees under intensive greenhouse culture. Exponentially increasing fertilizer additions stimulated ectomycorrhizal development (49-85%) compared with conventional constant-rate fertilization (22-26%). Exponential fertilization also increased seedling N (13-34%) and P (5-18%) uptake, although dry matter production was reduced (17-25%) at the lowest exponential addition rate. Ectomycorrhizal inoculation did not affect seedling biomass but increased uptake of N (6-17%), P (5-20%), and K (4-18%), demonstrating a potential for nutrient loading by fungi. Higher ectomycorrhizal formation found under exponential fertilization regimes was attributed to lower initial nutrient levels maintained in the growing media. Results indicate that high exponential fertilization combined with fungal inoculation may be effective for producing both nutrient-loaded and ectomycorrhizally infected planting stock.
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Castellano, Michael A., and James M. Trappe. "Ectomycorrhizal formation and plantation performance of Douglas-fir nursery stock inoculated with Rhizopogon spores." Canadian Journal of Forest Research 15, no. 4 (1985): 613–17. http://dx.doi.org/10.1139/x85-100.
Full textAbstract:
Basidiospores of seven species of hypogeous, ectomycorrhizal fungi were inoculated on four conifer species in a bare-root nursery. Inoculation with either Rhizopogonvinicolor Smith or Rhizopogoncolossus Smith succeeded with two provenances of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco). For R. vinicolor, the high spore-application rate produced the most mycorrhizae on the greatest number of seedlings. For R. colossus, the high spore-application rate produced the most mycorrhizae on the greatest number of seedlings of seed source 062, whereas the medium rate did better with seed source 252. Stem height and root collar diameter of seedling did not differ significantly between treatments and controls. Douglas-fir seedlings inoculated or not inoculated with spores of R. vinicolor were outplanted in southwestern Oregon. After 2 years, inoculated seedlings had significantly greater survival, stem height, root collar diameter, and biomass than noninoculated seedlings. Although new feeder roots of both noninoculated and inoculated seedlings were colonized by indigenous fungi, R. vinicolor persisted on the old root systems of inoculated seedlings and colonized new feeder roots.
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Silva, Cleidson Alves da, Jhonny Kelvin Dias Martins, João Batista Dias Damaceno, et al. "Formation of Seedlings of Coffea canephora Pierre ex Froehner and Weed Control Under Application of Herbicides Oxyfluorfen and Pendimethalin." Journal of Agricultural Science 11, no. 13 (2019): 312. http://dx.doi.org/10.5539/jas.v11n13p312.
Full textAbstract:
One of the most relevant factors for the formation of coffee crops is to use quality seedlings. However, the competition of weeds for nutrients and water from the soil can negatively affect your obtaining. Thus, the control of weeds in nursery is often dependent on the use of herbicides, considering that the manual activity is costly. In this way, this work aimed to evaluate the effectiveness of weed control and the effects on the development of clonal seedlings of coffee (Coffea canephora Pierre ex Froehner) by application of herbicides oxyfluorfen and pendimenthalin in nursery conditions. The experiment was conducted under a completely randomized design in factorial scheme 2 &times; 5, two herbicides: Pendimethalin and Oxifluorfen in five doses: corresponding to 0, 1, 2, 4, 8 L.ha-1 of commercial products. Was evaluated during the experiment the emergence of weeds and to end (140 days), were evaluated: seedling Height, stem diameter, leaf area, number of sheets, number of roots, root length, root volume, dry mass of roots and shoot dry matter. There was significant effect for seedling height, shoot dry matter and total dry mass, in which the pendimethalin caused damage to seedlings in comparison to oxyfluorfen. The use of the herbicides Pendimethalin and Oxyfluorfen obtained satisfactory control of weeds with application of 1080g and 648 g a.i. ha-1, respectively.
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Chakravarty, P., R. L. Peterson, and B. E. Ellis. "Integrated control of Fusarium damping-off in red pine seedlings with the ectomycorrhizal fungus Paxillusinvolutus and fungicides." Canadian Journal of Forest Research 20, no. 9 (1990): 1283–88. http://dx.doi.org/10.1139/x90-171.
Full textAbstract:
Damping-off caused by Fusariumoxysporum Schlecht. in red pine (Pinusresinosa Ait.) was significantly reduced when seedlings were treated with either of two fungicides (benomyl or oxine benzoate) concomitantly with the ectomycorrhizal fungus Paxillusinvolutus (Batsch.) Fr. compared with inoculation with P. involutus alone. Both fungicides at concentrations of 10 ppm and above significantly reduced spore germination and germ-tube length of F. oxysporuminvitro. On the other hand, invitro growth of P. involutus mycelium was not affected by the fungicides at concentrations up to 1000 ppm. The growth of P. involutus was, however, significantly reduced by the two fungicides at 5000 and 10 000 ppm. Inoculation of red pine seedlings with P. involutus was effective under growth chamber and greenhouse conditions in reducing the incidence of damping-off induced by F. oxysporum. When benomyl and oxine benzoate were applied in combination with P. involutus, seedling mortality was not observed. Oxine benzoate was phytotoxic and inhibited mycorrhiza formation by P. involutus at the recommended dose. Benomyl, on the other hand, had no inhibitory effect on seedling growth and stimulated ectomycorrhiza formation either by a naturally occurring mycorrhizal fungus or P. involutus in the greenhouse. The concept of incorporating integrated biological and chemical treatment for controlling Fusarium damping-off of red pine seedlings is suggested.
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Ohkawa, Kiyoshi, T. Yoshizumi, M. Korenaga, and K. Kanematsu. "Reversal of Heat-induced Resetting in Eustoma grandiflorum with Low Temperatures." HortScience 29, no. 3 (1994): 165–66. http://dx.doi.org/10.21273/hortsci.29.3.165.
Full textAbstract:
The effects of seedling age and temperature regimes and durations on the reversal of Eustoma grandiflorum (Raf.) Shin. heat-induced rosette formation were clarified. When E. grandiflorum seedlings were grown in a natural-light phytotron (600-800 μmol·m-2·s-1) for 4 weeks at 33/28C (12-h day/12-h night) from germination to the four true-leaf stage, the optimum temperature and duration required to break rosette formation was 15C for 4 weeks with continuous illumination (35 μmol·m-2·s-1). However, when seedlings were grown for 12 weeks at 33/28C from germination to the eight true-leaf stage. shoot elongation required 6 weeks at 10C.
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Medina, Edison Cardona, Marisa Santos, and Rubens Onofre Nodari. "Post-seminal structure and development of the hemiparasitic plant Escobedia grandiflora (Orobanchaceae)." Acta Scientiarum. Biological Sciences 41 (November 6, 2019): e46667. http://dx.doi.org/10.4025/actascibiolsci.v41i1.46667.
Full textAbstract:
Escobedia grandiflora (L.f.) Kuntze is a wild hemiparasitic plant with orange roots. Little is known about the development of initial parasitism with the host, despite the significant value of roots for Central and South American communities. Therefore, this study aimed to characterize post-seminal structure and development of E. grandiflora in Pennisetum purpureum host. To analyze the structure and development of E. grandiflora, seedlings, stems and roots samples were processed and examined under light, confocal and scanning electron microscopy. Escobedia grandiflora seeds are composed of seed coat, perisperm, and embryo. Emergence of the radicle began eleven days after imbibition. Seedlings showed a root hair collar encircling the axis at the root-hypocotyl junction with elongation of internal cortical cells. Seedlings formed haustoria and successfully reached of the host roots 22 days following root emergence. In the root many starch grains were observed, albeit more scarce in the hypocotyl. After 43 days of root emergence, the seedling stage was finished with the formation of the definitive leaves, and star of the plant stage. After 64 days, root ramification, amount of starch, and orange pigmentation increased with formation of haustoria. The developmental pattern of E. grandiflora plants was slow, but the roots grew faster than the stem. Escobedia grandiflora seeds were not endospermic and have limited nutritional value. After root emergence, the young seedling must develop roots and starch storage towards to haustorium formation and attachment to host roots.
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Wei, Hao, Jiangtao Hu, Chen Liu, et al. "Effect of Supplementary Light Source on Quality of Grafted Tomato Seedlings and Expression of Two Photosynthetic Genes." Agronomy 8, no. 10 (2018): 207. http://dx.doi.org/10.3390/agronomy8100207.
Full textAbstract:
Supplementary lighting is commonly used in high-quality seedling production. In this study, grafted tomato seedlings were grown for 10 days in a glasshouse with 16-h daily supplementary lighting at 100 μmol·m−2·s−1 PPFD (Photosynthetic photon flux density) from either high-pressure sodium (HPS), metal halide (MH), far-red (FR), white LEDs (Light emitting diodes) (W), or mixed LEDs (W1R2B1, where the subscript numbers indicate the ratio of the LED chips) to determine which light sources improve the seedling quality. The control seedlings did not receive any supplementary light. Physiological parameters and the expression of genes related to photosynthesis were analyzed. The results showed that root length, biomass, number of leaves, chlorophyll (SPAD), scion dry weight to height ratio (WHR), and specific leaf weight (SLW) were the greatest for grafted seedlings grown in W1R2B1. The level of root ball formation was the greatest for seedlings grown in W1R2B1, followed by those grown in W, HPS, and MH. Seedlings grown in FR did not fare well, as they were very thin and weak. Moreover, the expression of two photosynthetic genes (PsaA and PsbA) was significantly increased by W1R2B1 and W, which suggests that the plastid or nuclear genes might be regulated. The overall results suggest that W1R2B1 was the most suitable light source to enhance the quality of grafted tomato seedlings. The results of this study could be used as a reference for seedling production in glasshouses, and may provide new insights in the research on lights affecting the development of plants.
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White, PF, and AD Robson. "Emergence of lupins from a hard setting soil compared with peas, wheat and medic." Australian Journal of Agricultural Research 40, no. 3 (1989): 529. http://dx.doi.org/10.1071/ar9890529.
Full textAbstract:
The formation of a hard crust on a soil can severely decrease seedling emergence. The magnitude of the effect depends on a number of characteristics of the seed and seedling.The emergence of two species of lupin was compared with that of peas, wheat and medics. Seeds were sown into a sandy-clay loam where a hard crust was allowed to develop and where crust formation was reduced by the application of CaSO4.Emergence of seedlings with an epigeal pattern of emergence was reduced by crust formation. Emergence of Lupinus angustifolius and medics was severely reduced by crust formation, whereas emergence of the larger seeded L. albus was only slightly affected. In contrast to the epigeal seedlings, emergence of peas and wheat was unaffected by crust formation. Sowing lupins deeper exacerbated the problem.Seed size and pattern of emergence appeared to be the major factors determining the success of establishment of these species.
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Vdovenko, Serhii, Pavlo Shvydkyi, and Oleh Zatolochnyi. "INFLUENCE OF SEEDS AGE ON BIOMETRIC INDICATORS OF SWEET PEPPER UNDER CONDITIONS OF THE FOREST-STEPPE OF THE RIGHT-BANK OF UKRAINE." Agriculture and Forestry, no. 3 (October 30, 2020): 115–26. http://dx.doi.org/10.37128/2707-5826-2020-3-10.
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Sweet pepper takes one of the main places in the human diet among all vegetable plants. By the content of healthy vitamins, sweet pepper fruits have a better effect on the absorption of food than greenhouse cucumbers and tomatoes, and therefore sweet pepper is in great demand among consumers. The difference in the biometric and physiological parameters of sweet pepper of different age seedlings depends on the duration of growing seedlings. For the study, a sweet pepper variety of domestic selection Aphrodite was used. At the same time, biometric determinations were carried out over the sweet pepper plant: seedling height, stem diameter before planting, plant mass. The observation method monitored the onset of phenological phases of plant growth and development, and a laboratory method was used to determine biometric parameters. The appearance of the first leaf was established with clear control of the microclimate parameters and the provision of an appropriate irrigation regime. The formation of the first leaf was observed on the 7th day after emergence. It was proved that the formation of subsequent leaves, the growth of vegetative mass depended significantly on the age of the seedlings: the higher the seedling age, the more real leaves formed, due to the accumulation of dry matter in the leaves and the corresponding nutritional and temperature conditions. At the time of planting seedlings in open ground, at a constant place of vegetation, the plants were characterized by the presence of 4-6 real leaves, the height of the seedlings was 12-15 cm with a total weight of 10-12 g, there were no damage by pests and diseases on the surface of the leaves. As a result of different age of seedlings, studies have established that with a decrease in the age of seedlings, a tendency to delay flowering and fruiting was observed. The age of seedlings directly affects the budding of plants. So, in the variant where the seedlings are 60 days old, the period of budding was observed for 56 days, which was observed 1 day earlier than the control variant. Seedlings of sweet pepper aged 50 and 70 days passed into the budding phase for 57 days. However, seedlings aged 40 days showed a tendency to delay the onset of plant budding. It has been established that the height of the plant before planting ranged from 14.7 cm to 18.6 cm. The highest rate of plant growth has been distinquished in the variant where the seedlings were 70 days old. When using the seedling age of 70 days, the test value was 2 controls more than the control index. The option using 60 day old sweet pepper seedlings was characterized by slightly low leaf numbers. The experiments established that when using seedlings with an age of 40 days, the plants were characterized by the smallest number of leaves on the plant. The age of seedlings and biometric indicators depend on the growing conditions, the timely passage of the photosynthesis process, the provision of nutrients, water. When using the seedling age of 60-70 days, the biometric indicators of seedlings, namely the height of the plants, the number of glosses, the mass of the plant significantly exceeds the biometric indicators of seedlings with an age of 50 or 40 days. Keywords: sweet pepper, Aphrodite variety, seedling age, biometrics, vegetation, Right-Bank forest-steppe.
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Miller, Steven L., Therese M. McClean, Nancy L. Stanton, and Stephen E. Williams. "Mycorrhization, physiognomy, and first-year survivability of conifer seedlings following natural fire in Grand Teton National Park." Canadian Journal of Forest Research 28, no. 1 (1998): 115–22. http://dx.doi.org/10.1139/x97-195.
Full textAbstract:
Ectomycorrhiza formation, survivability, and physiognomic characteristics were assessed for conifer seedlings encountered 1 and 2 years postfire in the Huck burn site near Grand Teton National Park. Pinus contorta Dougl. ex Loud. germinated and was abundant throughout the first growing season. Abies lasiocarpa (Hook.) Nutt. germinated during May and June but was rarely encountered by September. First-year survivorship of P. contorta seedlings was about 50% for east-facing burn and edge and west-facing burn treatments. Mortality was higher in the west-facing edge treatment at about 64%. Pinus contorta seedlings collected in July and August had allocated approximately 75% more biomass to epicotyl production than to hypocotyl production, whereas by September seedlings had allocated 30-50% of their biomass to hypocotyls, regardless of site or treatment. Few or no ectomycorrhizae were formed until September. By September 100% of surviving seedlings were ectomycorrhizal. The number of ectomycorrhizae was positively correlated with the number of primary needles and the root/shoot ratio. These results highlight the importance of mycorrhizae to conifer seedling survival during the initial growing season and point to alteration of carbon allocation as a primary mechanism affecting seedling survival.
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Ka, Kang-Hyeon, Suk-Ju Jeong, and Hyun Park. "Ectomycorrhizal Formation of Ramaria botrytis Using Pinus densiflora Seedling." Korean Journal of Mycology 37, no. 1 (2009): 111–13. http://dx.doi.org/10.4489/kjm.2009.37.1.111.
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Dąbrowska, Janina. "Problematic octaploid forms and a new chromosome number in the genus Achillea L., 2n = 126." Acta Societatis Botanicorum Poloniae 58, no. 2 (2014): 179–84. http://dx.doi.org/10.5586/asbp.1989.014.
Full textAbstract:
Among the offspring of a problematic form of <em>Achillea sp., </em>a 2n = 126 seedling which probably arose as the result of fusion of unreduced octo- and hexaploid gametes (72 + 54) was found along with seedlings having an octaploid chromosome number (2n = 72). Putative paths leading to the formation of problematic octaploid forms and plants with 126 chromosomes are discussed.
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Amorim, Scheila Antunes, Augusto Miguel N. Lima, Ítalo Herbert Lucena Cavalcante, et al. "Sugar apple seedling production as a function of substrates and slow-release fertilizer." Comunicata Scientiae 11 (October 5, 2020): e3146. http://dx.doi.org/10.14295/cs.v11i.3146.
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There is still a lack of studies on the effect of slow-release fertilizers and substrates on the production of high-quality sugar apple seedlings. In this context, the present study aimed to evaluate the quality and biomass of sugar apple seedlings grown in organic substrates at doses of slow-release fertilizer. The experimental design was randomized blocks in split-plot scheme, with four replicates and eleven plants per plot. Substrates were evaluated in the plots (fresh sugarcane bagasse; enriched sugarcane bagasse; coconut powder; commercial organic substrate Tropstrato®), whereas the doses of the slow-release fertilizer Osmocote® were evaluated in the subplots (0; 3; 6; 9; 12 and 15 kg m-3 of substrate). Substrates and slow-release fertilizer doses had effect on the formation of sugar apple seedlings. The effect of slow-release fertilizer is influenced by the substrate used in the formation of sugar apple seedlings. The substrate coconut powder showed the best performance for E%, NL and LAI in sugar apple plants, which reinforces its recommendation to be used in seedling production. For the studied conditions, based on the DQI, we recommend coconut powder associated with the slow-release fertilizer dose of 9 kg m-3 to produce sugar apple seedlings.
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Stephenson, Katherine Kelly, John R. Stommel, and Timothy J. Ng. "Feasibility Studies for in Vitro Grafting and Chimera Formation among Lycopersicon spp." HortScience 32, no. 3 (1997): 449B—449. http://dx.doi.org/10.21273/hortsci.32.3.449b.
Full textAbstract:
A protocol was developed to make in vitro graft unions among Lycopercicon spp., and regenerates from cultured graft unions were evaluated for chimera formation. Young seedlings were preconditioned for 4 to 6 days in liquid 1/2-strength Murashige & Skoog (MS) basal medium supplemented with 8.9 μM benzyladenine and 1.0 μM indole-3-butyric acid. Preconditioned seedlings exhibited increased biomass and enhanced graft union survival. In particular, survival of cleft grafts increased from 37% to 95% with the seedling preconditioning. When graft unions among different genotypes were excised from apex-to-apex in vitro cleft grafts and plated on MS basal medium supplemented with 9.1 μM zeatin and 3.9 μM ancymidol, as many as 100 plantlets were regenerated from a single graft union. However, no chimeric regenerates were recovered, indicating that asymmetric responses to grafting may be a limiting factor to in vitro chimera formation.