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Journal articles on the topic 'Seedling Response'
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1
Islam, Sumaiya, Md Nasim Reza, Shahriar Ahmed, et al. "Seedling Growth Stress Quantification Based on Environmental Factors Using Sensor Fusion and Image Processing." Horticulturae 10, no. 2 (2024): 186. http://dx.doi.org/10.3390/horticulturae10020186.
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Understanding the diverse environmental influences on seedling growth is critical for maximizing yields. The need for a more comprehensive understanding of how various environmental factors affect seedling growth is required. Integrating sensor data and image processing techniques offers a promising approach to accurately detect stress symptoms and uncover hidden patterns, enhancing the comprehension of seedling responses to environmental factors. The objective of this study was to quantify environmental stress symptoms for six seedling varieties using image-extracted feature characteristics. Three sensors were used: an RGB camera for color, shape, and size information; a thermal camera for measuring canopy temperature; and a depth camera for providing seedling height from the image-extracted features. Six seedling varieties were grown under controlled conditions, with variations in temperature, light intensity, nutrients, and water supply, while daily automated imaging was conducted for two weeks. Key seedling features, including leaf area, leaf color, seedling height, and canopy temperature, were derived through image processing techniques. These features were then employed to quantify stress symptoms for each seedling type. The analysis of stress effects on the six seedling varieties revealed distinct responses to environmental stressors. Integration of color, size, and shape parameters established a visual hierarchy: pepper and pak choi seedlings showed a good response, cucumber seedlings showed a milder response, and lettuce and tomato seedlings displayed an intermediate response. Pepper and tomato seedlings exhibited a wide range of growth stress symptoms, at 13.00% to 83.33% and 2.96% to 70.01%, respectively, indicating considerable variability in their reactions to environmental stressors. The suggested classification approach provides valuable groundwork for advancing stress monitoring and enabling growers to optimize environmental conditions.
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Landhäusser, Simon M., Erin T. Wiley, Kevin A. Solarik, Shaun P. Kulbaba, and Alexander E. Goeppel. "The Importance of Initial Seedling Characteristics in Controlling Allocation to Growth and Reserves under Different Soil Moisture Conditions." Forests 14, no. 4 (2023): 796. http://dx.doi.org/10.3390/f14040796.
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After disturbance, forest regeneration and resiliency depend on the ability of seedlings to respond, survive, and grow under a variety of stress conditions, including drought. Despite recent efforts to improve our fundamental knowledge surrounding plant response mechanisms to stress and their application in seedling quality research, initial seedling characteristics are often ignored when exploring seedling responses to stress in field plantings or ecophysiological studies. Here, we explore how initial differences in size, biomass allocation, and non-structural carbohydrate (NSC) storage affect the subsequent partitioning of new biomass, growth potential, and drought response in seedlings of a deciduous broad-leaved (Populus tremuloides) and an evergreen coniferous species (Pinus banksiana). We exposed seedlings of both species to different growing conditions in their first growing season in order to manipulate the aforementioned seedling characteristics. In a second growing season, we exposed these different seedling types to a subsequent drought stress. While drought reduced both structural growth and NSC storage in all seedling types, the expected shift in allocation favoring roots was only observed in seedling types with initially low root:shoot or root:stem ratios. Overall, we also found that the traits associated with greater growth were quite different between pine and aspen. While larger seedlings led to greater growth in pine, it was the smallest seedling type in aspen with the largest root:stem ratio that produced the most new growth. In aspen, this smaller seedling type was the only one that did not undergo a shift in biomass relative to its initial allometry, suggesting that adjustments in biomass allocation made by other, larger seedling types must have come at the cost of lower growth. In contrast, adjustments in allocation did not appear to negatively impact pine, possibly because reduced root:shoot ratios of larger seedlings did not reduce NSC storage, as it did in aspen. Our results highlight (1) the complexity of how differences in biomass allocation and changes in seedling size may alter storage and the response of species to drought, and (2) the importance of accounting for initial seedling characteristics (both morphological and physiological) when predicting seedling growth and the impacts of environmental stressors.
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Moore, James A., Zhaofei Fan, and Bahman Shafii. "Effect of Root-Plug Incorporated Controlled-Release Fertilizer on Two-Year Growth and Survival of Planted Ponderosa Pine Seedlings." Western Journal of Applied Forestry 17, no. 4 (2002): 216–19. http://dx.doi.org/10.1093/wjaf/17.4.216.
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Abstract Three controlled-release fertilizers (fast release [FR], moderate release [MR], and slow release [SR]) were incorporated in the root plug at rates of 0.8, 1.6, or 3.2 g/seedling at the time of sowing as supplements to nursery supplied soluble fertilizer. Effects on seedling growth, survival, and foliar nutrient status of the “160/90” container ponderosa pine (Pinus ponderosa) were evaluated after outplanting. At the end of the second growing season, fertilized seedlings had significantly greater diameter and height than unfertilized seedlings. The 3.2 g of MR or SR fertilizer treatments produced significantly higher mortality (55 and 36%, respectively) than the controls. The fast release fertilizer included at a rate of 0.8 g in each seedling's container was the preferred treatment since it produced good survival and seedling growth response. A 2-yr growth response of about 25% was similar to that observed in a nearby study using adjacent placement of controlled-release fertilizer after planting ponderosa pine seedlings. West. J. Appl. For. 17(4):216–219.
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Sayar, R., H. Bchini, M. Mosbahi, and H. Khemira. "Response of durum wheat (Triticum durum Desf.) growth to salt and drought stresses." Czech Journal of Genetics and Plant Breeding 46, No. 2 (2010): 54–63. http://dx.doi.org/10.17221/85/2009-cjgpb.
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Two durum wheat (Triticum durum Desf.) cultivars were tested for salt and drought tolerance at germination, seedling emergence and early seedling growth in NaCl and PEG-8000 solutions of different osmotic potentials (–0.2, –0.4, –0.6 and –0.8 MPa). Daily and final germination and emergence percentage, as well as germination and seedling emergence rate, seedling growth, fresh and dry weight were recorded under controlled conditions. Results showed that germination and emergence rates were delayed by both solutions in both cultivars, but Omrabia showed higher germination and emergence rates than BD290273 in NaCl while BD290273 was less affected by NaCl and PEG solutions at the emergence stage. Sodium chloride had a lesser effect on both cultivars in terms of germination rate, emergence rate, final germination and emergence percentage than did PEG-8000. This conclusively proves that the adverse effect of PEG-8000 on germination, emergence and early seedling growth was due to the osmotic effect rather than to the specific ion. Seedling growth was reduced by both stresses. However, NaCl usually caused less damage than PEG to durum wheat seedlings, suggesting that NaCl and PEG acted through different mechanisms.
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Ross, Darrell W., and C. Wayne Berisford. "Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) Response to Water and Nutrient Status of Loblolly Pine." Forest Science 36, no. 3 (1990): 719–33. http://dx.doi.org/10.1093/forestscience/36.3.719.
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Abstract Loblolly pine (Pinus taeda L.) seedlings were grown in a greenhouse under conditions of variable water and nutrient availability and then exposed to natural populations of the Nantucket pine tip moth (Rhyacionia frustrana [Comstock]). Seedling growth was directly related to water and nutrient availability. Tip moth oviposition was highest on the most vigorous seedlings, even after accounting for differences in seedling size among treatments. The ratios of mean number of pupae per seedling to mean number of eggs per seedling for each treatment indicated percent tip moth survival may have been lower on vigorous seedlings than on stressed seedlings, but differences may have been due to factors other than the suitability of seedlings as larval food. Larger numbers of heavier pupae developed on vigorous seedlings than on stressed seedlings. Pupal weights were directly related to total nitrogen concentration and inversely related to total phenolic and condensed tannin concentrations of pine shoot tissues. Total phenolic and condensed tannin concentrations were inversely related to seedling growth. These results suggest that tip moth populations will increase rapidly following silvicultural treatments that increase water and nutrients available to young loblolly pines. For. Sci. 36(3):719-733.
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O'Neill, G. A., C. P. Chanway, P. E. Axelrood, R. A. Radley, and F. B. Holl. "An assessment of spruce growth response specificity after inoculation with coexistent rhizosphere bacteria." Canadian Journal of Botany 70, no. 12 (1992): 2347–53. http://dx.doi.org/10.1139/b92-294.
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The influence of inoculation with rhizosphere bacteria on hybrid spruce (Picea glauca × engelmannii) seedling growth was investigated by isolating bacteria from the rhizosphere of naturally regenerating spruce seedlings collected from two ecologically distinct zones of British Columbia. Forty bacterial strains from spruce were screened in a seedling growth experiment, and several strains were shown to stimulate spruce seedling growth. The three most effective spruce growth promoting strains from each ecological zone were then tested in a seedling growth response specificity experiment in which seed, soil, and bacteria from both spruce ecosystems were examined in all possible treatment combinations, including pasteurized soil. Spruce seedling growth was primarily affected by seed and soil source (Salmon Arm > Mackenzie for both factors), and by soil pasteurization (pasteurized > unpasteurized). Significant growth effects due to bacterial treatment in the specificity experiment occurred only in pasteurized soil, but seedling biomass accumulation was stimulated by up to 59% in response to inoculation. There was no evidence of growth response specificity that was related to plant – bacteria adaptation within spruce ecotypes; two of the Mackenzie bacterial strains significantly inhibited growth of Mackenzie seedlings in Mackenzie soil, but two strains stimulated the growth of Salmon Arm seedlings, one in each soil type. Two Salmon Arm strains significantly stimulated growth of Mackenzie seedlings on Salmon Arm soil, and two strains stimulated the growth of Salmon Arm seedlings, one in each soil type. Seedling biomass was greater when treatments of spruce seed, soil, and rhizosphere bacteria that originated from the same geographic site were pooled and compared with treatments in which at least one factor originated from the other site. However, this effect was explained by the significant seed × soil interaction in the absence of bacteria; mean seedling biomass was greatest when spruce seed and soil treatments with the same geographic origin were pooled and compared with unrelated seed – soil combinations. Seedlings from pooled treatments were also significantly larger when bacteria and soil had a common geographic origin, but only when tested in pasteurized soil. Our results indicate that spruce growth promoting rhizosphere bacteria can be isolated from naturally regenerating spruce seedlings, but growth response variability was observed between trials. Seedling growth promotion by bacterial strains was not related to the use of spruce ecotypes, soil, and (or) rhizosphere bacteria with a common geographic origin. Key words: spruce seedlings, growth, inoculation, rhizosphere bacteria.
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Edelman, Nichole F., and Michelle L. Jones. "Evaluating Ethylene Sensitivity within the Family Solanaceae at Different Developmental Stages." HortScience 49, no. 5 (2014): 628–36. http://dx.doi.org/10.21273/hortsci.49.5.628.
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The family Solanaceae, which includes both important crop and ornamental species, is generally considered to have high sensitivity to ethylene. Our objectives were to evaluate ethylene sensitivity between accessions with the family Solanaceae and to determine whether similar sensitivity was observed in seedlings and mature plants. For the seedling evaluations, seeds were germinated and grown in the dark on filter paper saturated with 0 or 100 μM 1-aminocyclopropane-1-carboxylic acid (ACC; the immediate precursor to ethylene). The relative hypocotyl length at 100 μM ACC was compared with untreated control (0 μM) seedlings. Mature plants were treated with 0 or 10 μL·L−1 ethylene in the dark for 24 hours. Ethylene responses including flower abscission, flower senescence, and epinasty were observed and quantified. Seedlings and mature plants were classified as having no response, low, medium, or high ethylene sensitivity based on the severity of the ethylene responses observed. Sensitivity differences were observed among seedling, juvenile, and mature plants, and a range of ethylene responses and symptom severity was observed between accessions within a species. The majority of the accessions were classified as medium or high ethylene sensitivity at both the seedling and mature plant stages. Solanum melongena ‘Black Beauty’ (eggplant) had a low response to ethylene at the seedling stage and a high response at the mature plant stage, whereas Petunia ×hybrida ‘Daddy Orchid’ had a high response at the seedling stage and a low response at the mature plant stage. Peppers (Capsicum annum), tomatoes (Solanum lycopersicum), and tomatillos (Physalis ixocarpa) exhibited both floral and vegetative symptoms of ethylene damage, whereas calibrachoas (Calibrachoa ×hybrida), eggplants, nicotianas, and petunias exhibited only floral symptoms. The most common floral response to ethylene treatment was flower abscission, which was observed in almost all of the Solanum, Capsicum, and Nicotiana accessions. We consistently observed ethylene-induced epinasty in the genus Capsicum and in all of the Solanum except eggplant. Our results indicated that developmental stage influenced ethylene sensitivity, and there was not a consistent correlation between seedling and mature plant responses within the Solanaceae accessions that we evaluated.
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Frisby, James W., and Schuyler D. Seeley. "CHILLING OF PEACH SEEDS, SEEDLINGS AND CUTTINGS." HortScience 25, no. 9 (1990): 1088f—1088. http://dx.doi.org/10.21273/hortsci.25.9.1088f.
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Correlations were made between the responses of seeds, physiologically dwarfed seedlings and dormant cuttings to similar chilling treatments. Seed germination correlated highly with growth of physiologically dwarfed seedlings and shoot growth of dormant cuttings. Emergence and seedling growth correlated poorly with germination, growth of physiologically dwarfed seedlings and shoot growth of dormant cuttings. Thus, germination was a better seed predictor of the mature peach chilling response than emergence or seedling growth. Growth of dwarfed seedlings correlated highly with shoot growth of dormant cuttings. The anomalous leaf condition of peach seedlings may have confounded seedling growth after seed chilling, but was not a problem when the chilling treatment was provided to physiologically dwarfed seedlings. The dormancy release mechanisms that promoted seed germination, growth of physiologically dwarfed seedlings and growth of dormant cuttings were similar.
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Al-Din, N. S., and A. H. Alalaf. "Response of Seedlings of Two Olive Varieties to the Addition of Chemical and Biological Fertilization." IOP Conference Series: Earth and Environmental Science 1449, no. 1 (2025): 012137. https://doi.org/10.1088/1755-1315/1449/1/012137.
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Abstract Nursery owners suffer from slow growth of olive seedlings, and thus production costs increase until they are ready for planting in a sustainable orchard. Therefore, this study aimed to add biological and chemical fertilization to seedlings of two types of olives for the purpose of improving their growth and mineral content. The experiment included two factors, the first nine fertilizer treatments containing 15gm. Seedling−1NPK (20:20:20), 10g.Seedling−1NPK+5g.Seedling−1 Biofertilizer Gorabac G, 5g.Seedling−1NPK+10g.Seedling−1 Biofertilizer Gorabac G, 2.5g.Seedling−1NPK +15g. Seedlings−1 Biofertilizer Gorabac G, 20g. Seedlings−1 Biofertilizer Gorabac G, 10g. Seedlings−1NPK+5ml.Seedlings−1Biofertilizer in broth form, 5g.Seedlings−1NPK+10ml.Seedlings−1 Biofertilizer In broth form, 2.5 gm. Seedling−1 NPK + 15 ml. Seedling−1 Biofertilizer in broth form, 20 ml. Seedling−1 biofertilizer in broth form. The second factor included two olive varieties (Nabali and Sourani), according to the results measured at the end of the experiment. It was found that there were no significant differences between the factors for the (leaf content of phosphorus, potassium, nitrogen, protein, and dry weight of the root system). On the other hand, the treatment 10 g. seedling−1 NPK + 5 ml. seedling−1 biofertilizer in broth form was superior to the rest of the treatments in terms of dry weight of the shoot, as well. The Nabali variety was significantly superior to the Sorani variety in the values of this trait.
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Singh, Nidhi, A. Saxena, and R. Singh. "Growth responses of Jatropha Curcas seedlings under different soil mixtures, fertilizer doses, irrigation regimes and sodicity levels." Journal of Non-Timber Forest Products 17, no. 2 (2010): 163–71. http://dx.doi.org/10.54207/bsmps2000-2010-05mv72.
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The present study analyses the growth responses of Jatropha curcas seedlings under different soil mixtures, fertilizer doses, irrigation frequency and soil sodicity levels. Among all the soil mixtures, seedlings of J. curcas indicated higher growth, dry weight and quality index in the mixture of soil, sand and FYM in 1:2: 2 and 1: 1: 2 ratios. Further, increasing FYM in all the combinations of soil mixture increased the seedling growth. However, increase of sand in the soil mixture beyond 1: 2: 2 ratios of soil, sand and FYM did not improve the seedling growth. The application of NPK fertilizers in soil @ 100: 75: 75 mg per seedling showed maximum growth, dry weight and quality index of seedlings. It was also observed that application of N in higher doses reduced the seedling growth and dry weight. The seedlings of this species relatively performed better up to low moisture stress level than under intermediate and high moisture stress levels. Root dry weight and root: shoot ratio, however, increased with increasing the moisture stress levels. Under various soil sodicity levels, the response of J. curcas seedlings indicated a marked reduction in growth and dry weight with increasing levels of sodicity. Further, the response breadths were comparatively lower under sodicity levels than under soil mixture, fertilizer doses and moisture stress levels.
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Joesting, Heather M., Brian C. McCarthy, and Kim J. Brown. "The photosynthetic response of American chestnut seedlings to differing light conditions." Canadian Journal of Forest Research 37, no. 9 (2007): 1714–22. http://dx.doi.org/10.1139/x07-039.
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Restoration attempts to reintroduce American chestnut trees to the eastern deciduous forest by means of a disease-resistant Chinese–American hybrid seed are in progress. Knowing the light conditions required for optimum seedling performance is necessary to maximize the success of reintroduction. American chestnut ( Castanea dentata (Marsh.) Borkh.) seedlings were planted in two replicate forests in Vinton County, Ohio, in areas that had been thinned (more available light) and in control areas (intact canopy, less available light). The photosynthetic capacity of 12 seedlings per treatment was assessed using an infrared gas-exchange analyzer. Seedlings in the thinned treatment reached light-saturating rates of photosynthesis at an irradiance level approximately 33% higher than did the seedlings in the control treatment. Seedlings grown in the thinned treatment had a significantly greater maximum rate of photosynthesis (Amax), dark respiration rate (Rd), and daily carbon gain per seedling than seedlings grown in the control treatment. The light compensation point (LCP), quantum efficiency (ϕ), leaf mass per area (LMA), and leaf nitrogen concentration per unit leaf area (Narea) were not significantly different between treatments. American chestnut seedlings in the thinned treatment clearly maximize leaf-level photosynthetic capacity. These results will aid land managers in planning reintroduction trials by providing information on the light conditions required for maximum seedling success.
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Firdaus, N. K., I. Sobari, D. Pranowo, K. D. Sasmita, E. Wardiana, and Saefudin. "Growth response of Meranti Liberoid coffee seedling to liquid organic fertilizer and dolomite application." IOP Conference Series: Earth and Environmental Science 1230, no. 1 (2023): 012203. http://dx.doi.org/10.1088/1755-1315/1230/1/012203.
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Abstract Liberica coffee is a type of coffee that can grow in soils with low pH and low nutrients. One of the efforts to increase the strength of the coffee seedling is by improving the planting media, through organic fertilizers and ameliorants application. This study aimed to analyze the effect of liquid organic fertilizer (LOF) and dolomite on the growth of Meranti Liberoid 2 (LIM 2) coffee seedlings. This research was conducted at the Pakuwon Experimental Station, Sukabumi, from April 2021 to January 2022. The research design used was a factorial 2 factor with 3 replications. The first factor was the LOF concentration (0, 5, and 10%), and the second was the dolomite dose (0; 2.5; 5.0; 7.5; and 10 g seedling−1). The results showed that the highest seedling height, leaf, and root dry weight of LIM 2 coffee seedlings was achieved by dolomite treatment of 7.5 g seedling−1 without LOF. The use of LOF can be an alternative to the need for dolomite to increase the growth of LIM 2 coffee seedlings.
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Fadhil, Ayad Hasan, and Raad Taha Muhammad Ali Balaket. "Response of Seedlings of Three Cultivars of Mandarin to Spraying and Addition of Nano-Fertilizer." IOP Conference Series: Earth and Environmental Science 1371, no. 4 (2024): 042026. http://dx.doi.org/10.1088/1755-1315/1371/4/042026.
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Abstract The effect of spraying with nano-fertilizer at three levels (0, 2, 3) gm/liter and ground application was studied in the lathhouse of Al-Furat Al-Awsat Technical University / Al-Musayyib Technical College in Babylon province from March to December 2023. Nanofertilizer at 0, 0.5, and 1 g/anvil on three mandarin seedlings. A factorial experiment using the randomised complete block design (RCBD) with three replicates and three seedlings per unit was conducted. The experiment had 27 treatments randomly divided among 243 one-year-old seedlings. A Genstat ANOVA table was used to analyse these results. The least significant difference L.S.D. at 0.05 was used to compare treatments. The key findings are: Seedling height and average leaf area were best in the Clementine cultivar (96.36 cm, 1715.4 cm2 seedling-1). Leaf nitrogen and potassium were 2.61% and 1.48%, respectively. Spraying shoots with 3 g.L-1 nano-fertilizer increased seedling height, average leaf area, nitrogen, phosphorus, and potassium at the highest rate. The addition of nano-fertilizer significantly affected vegetative growth and leaf mineral content. Adding 1 g.pot-1 increased seedling height, average leaf area, nitrogen, phosphorus, and potassium the most. The double interaction between the Clementine cultivar and spraying with nano-fertilizer at 3 g.L-1 (A2B3) increased seedling height, average leaf area, nitrogen, potassium, and phosphorus percentage. The double interaction between the Clementine cultivar and nano-fertilizer with a concentration of 1 g.pot-1 (A2C3) significantly increased nitrogen, seedling growth rate, phosphorus, and potassium. Spraying nano-fertilizer at 3 g.L-1 and 1 g.plot-1 (B3C3) significantly enhanced seedling height, average leaf area, nitrogen, phosphorus, and potassium. The triple interaction between study factors increased characteristics, with A2B3C3 excelling in seedling height, average leaf area, and nitrogen.
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Čėsnienė, Ieva, Diana Miškelytė, Vitalij Novickij, Vida Mildažienė, and Vaida Sirgedaitė-Šėžienė. "Seed Treatment with Electromagnetic Field Induces Different Effects on Emergence, Growth and Profiles of Biochemical Compounds in Seven Half-Sib Families of Silver Birch." Plants 12, no. 17 (2023): 3048. http://dx.doi.org/10.3390/plants12173048.
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In the context of climate change, strategies aimed at enhancing trees’ resistance to biotic and abiotic stress are particularly relevant. We applied an electromagnetic field (EMF) seed treatment to observe changes in the establishment and content of biochemical compounds in silver birch seedlings induced by a short (1 min) seed exposure to a physical stressor. The impact of EMF treatment was evaluated on seedling emergence and growth of one-year-old and two-year-old seedlings from seven half-sib families of silver birch. The effects on numerous biochemical parameters in seedling leaves, such as total phenolic content (TPC), total flavonoid content (TFC), amounts of photosynthetic pigments, total soluble sugars (TSS), level of lipid peroxidation level, antioxidant activity and activity of antioxidant enzymes, were compared using spectrophotometric methods. The results indicated that, in one-year-old seedlings, two of seven (60th and 73rd) half-sib families exhibited a positive response to seed treatment with EMFs in nearly all analyzed parameters. For example, in the 60th family, seed treatment with EMFs increased the percentage of emergence by 3 times, one-year-old seedling height by 71%, leaf TPC by 47%, antioxidant activity by 2 times and amount of chlorophyll a by 4.6 times. Meanwhile, the other two (86th and 179th) families exhibited a more obvious positive response to EMF in two-year-old seedlings as compared to one-year-old seedling controls. The results revealed that short-term EMF treatment of silver birch seeds can potentially be used to improve seedling emergence and growth and increase the content of secondary metabolites, antioxidant capacity and photosynthetic pigments. Understanding of the impact of EMFs as well as the influence of genetic differences on tree responses can be significant for practical applications in forestry. Genetic selection of plant genotypes that exhibit positive response trends can open the way to improve the quality of forest stands.
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Černiauskas, Valentinas, Iveta Varnagirytė-Kabašinskienė, Ieva Čėsnienė, Emilis Armoška, and Valda Araminienė. "Response of Tree Seedlings to a Combined Treatment of Particulate Matter, Ground-Level Ozone, and Carbon Dioxide: Primary Effects." Plants 14, no. 1 (2024): 6. https://doi.org/10.3390/plants14010006.
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Trees growing in urban areas face increasing stress from atmospheric pollutants, with limited attention given to the early responses of young seedlings. This study aimed to address the knowledge gap regarding the effects of simulated pollutant exposure, specifically particulate matter (PM), elevated ozone (O3), and carbon dioxide (CO2) concentrations, on young seedlings of five tree species: Scots pine (Pinus sylvestris L.); Norway spruce (Picea abies (L.) H.Karst.); silver birch (Betula pendula Roth); small-leaved lime (Tilia cordata Mill.); and Norway maple (Acer platanoides L.). The main objectives of this paper were to evaluate the seedling stem growth response and the biochemical response of seedling foliage to pollutant exposure. Four treatments were performed on two- to three-year-old seedlings of the selected tree species: with PM (0.4 g per seedling) under combined O3 = 180 ppb + CO2 = 650 ppm; without PM under combined O3 = 180 ppb + CO2 = 650 ppm; with PM (0.4 g per seedling) under combined O3 < 40–45 ppb + CO2 < 400 ppm; and without PM under combined O3 < 40–45 ppb + CO2 < 400 ppm. Scots pine and Norway maple showed no changes in growth (stem height and diameter) and biochemical parameters (photosynthetic pigments, total polyphenol content (TPC), total flavonoids content (TFC), and total soluble sugars (TSS)), indicating a neutral response to the combined PM, O3, and CO2 treatment. The chlorophyll response to PM alone and in combination with elevated O3 and CO2 exposure varied, with silver birch increasing, Norway maple—neutral to increasing, Scots pine—neutral to decreasing, and Norway spruce and small-leaved lime—decreasing. The TPC indicated stress responses in Scots pine, small-leaved lime, and Norway maple under increased combined O3 and CO2 and in Norway spruce under single PM treatment. Hence, Scots pine and Norway maple seedlings showed greater resistance to increased PM under combined O3 and CO2 with minimal change in growth, while silver birch seedlings showed adaptation potential with increasing chlorophyll under simulated pollutant stress.
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Cinar, Gulcan, and Muhittin Dogan. "Physiological response of Moringa oleifera exposed to bisphenol A." Botanica Serbica 44, no. 2 (2020): 183–89. http://dx.doi.org/10.2298/botserb2002183c.
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The physiological and morphological effects of different concentrations of bisphenol A (BPA) on Moringa oleifera seedlings were determined in this study. Significant chlorosis and abscission were observed in leaves exposed to 50 mg/L of BPA. Photosynthetic pigment levels were affected differently by varying doses of BPA. Although the total carbohydrate content of seedling parts was increased by BPA, protein content was lowered by it, except in the case of roots at 1.5 mg/L of BPA. However, it was determined that the content of nonprotein sulphhydryl groups of seedling parts did not change significantly. The total phenolic content of root tissues showed an insignificant change; however, it was found that phenolic content increased in the stems and leaves following application of BPA. The content of hydrogen peroxide (H2O2) in seedling tissues increased with increasing concentrations of BPA. Statistical analysis indicated that H2O2 content was significantly correlated with malondialdehyde content. These results clearly show that the application of BPA causes oxidative stress in seedling tissues.
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McCreary, Douglas D., and Joe B. Zaerr. "Root respiration has limited value for assessing Douglas-fir seedling quality." Canadian Journal of Forest Research 17, no. 9 (1987): 1144–47. http://dx.doi.org/10.1139/x87-175.
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Root damage is a principal cause of poor seedling quality. Currently, the most widely used seedling-quality test measures a seedling's ability to initiate and elongate roots in a favorable environment; however, this test requires a lengthy response period and tedious, time-consuming measurements. Alternatively, the respiration rate of roots could be measured much more quickly and easily. Results of this study, which examined whether root respiration could successfully predict the survival and growth of potted Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings in a growth room, indicated that respiration may help assess root damage caused by desiccation but not that caused by freezing, hot storage, or rapid heating.
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Ali, R. M., and H. M. Abbas. "Response of salt stressed barley seedlings to phenylurea." Plant, Soil and Environment 49, No. 4 (2011): 158–62. http://dx.doi.org/10.17221/4107-pse.
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The effect of phenylurea with reported cytokinin-like activities on seed germination, seedling growth, activities of antioxidant enzymes, polyphenol, peroxidase, indoleacetic acid oxidase, and total phenolic compounds, flavonoids was investigated in stressed barley seedlings. The application of phenylurea decreases the activity of peroxidase, indoleacetic acid oxidase and increases the activity of polyphenol oxidase with decrease in total phenolic compounds and flavonoids and consequent increase in growth rate. Saline (NaCl) stress in barley seedlings causes an increase in total phenolic compounds, flavonoids and enhancement of peroxidase and indoleacetic acid oxidase activities and consequent decrease in growth rate. The adverse effect of salt stress on germination, antioxidant enzymes, phenolic compounds, flavonoids can partially be rectified by phenylurea.
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Johnson, W. C., and B. G. Mullinix. "Peanut Seedling Response to Dinitroaniline Herbicides Applied Preplant Incorporated and Preemergence1." Peanut Science 26, no. 1 (1999): 28–32. http://dx.doi.org/10.3146/i0095-3679-26-1-7.
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Abstract Greenhouse studies were conducted in 1995, 1996, and 1998 to measure the effect of preplant incorporated (PPI) and preemergence (PRE) applications of ethalfluralin and pendimethalin on growth of individual peanut seedlings in pots. Herbicide rates evaluated were 0, 0.6, 1.1, and 2.2 kg ai/ha for each herbicide. Parameters measured were time of emergence, seedling height, canopy width, foliage biomass, root length, and root biomass of individual plants. PPI applications were more injurious than PRE applications for all parameters regardless of herbicide. Ethalfluralin PPI inhibited peanut seedling growth more than equivalent rates of pendimethalin PPI. However, peanut seedling responses to PRE applications of ethalfluralin and pendimethalin were generally the same.
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Chanway, C. P., and F. B. Holl. "Ecological growth response specificity of two Douglas-fir ecotypes inoculated with coexistent beneficial rhizosphere bacteria." Canadian Journal of Botany 72, no. 5 (1994): 582–86. http://dx.doi.org/10.1139/b94-077.
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The influence of inoculation with rhizosphere bacteria on Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedling emergence in a controlled environment and on survival and growth in the field was investigated. Seed or seedlings of interior and coastal Douglas-fir ecotypes originating from the vicinity of Williams Lake and Chilliwack, British Columbia, Canada, respectively, were inoculated with two strains of rhizosphere bacteria, Arthrobacter oxydans strain N74 and Pseudomonas aureofaciens strain K23. These strains were previously isolated from naturally regenerating Douglas-fir seedlings collected from the Williams Lake and Chilliwack sites, respectively. Seed inoculation with either strain of bacteria, K23 or N74, stimulated the rate of seedling emergence, but these effects were not ecotype specific. While inoculation did not affect germination percentage, ecotype-specific seedling growth responses were detected 13 months after field planting. Arthrobacter oxydans strain N74 significantly stimulated seedling branching and enhanced root and shoot dry weight of the Williams Lake ecotype but had no significant stimulatory effect on growth of the Chilliwack ecotype. Pseudomonas aureofaciens strain K23 significantly stimulated shoot branching and root dry weight of Chilliwack Douglas-fir but had no significant stimulatory effect on growth of that from Williams Lake. When treatments of Douglas-fir seedlings and rhizosphere bacteria that originated from the same geographic site were pooled and compared with uninoculated controls, significant increases in shoot branch number and root dry weight were also detected. No significant difference in seedling growth was detected when treatments of seedlings and bacteria that originated from different sites were pooled and compared with uninoculated controls. Based on these results, we hypothesize that plant–microbe specificity may be an important component of Douglas-fir – beneficial rhizosphere bacteria interactions in the field. Key words: Douglas-fir seedlings, emergence, growth, rhizosphere bacteria, inoculation.
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Barrit, Thibault, Elisabeth Planchet, Jérémy Lothier, et al. "Nitrogen Nutrition Modulates the Response to Alternaria brassicicola Infection via Metabolic Modifications in Arabidopsis Seedlings." Plants 13, no. 4 (2024): 534. http://dx.doi.org/10.3390/plants13040534.
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Little is known about the effect of nitrogen nutrition on seedling susceptibility to seed-borne pathogens. We have previously shown that seedlings grown under high nitrate (5 mM) conditions are less susceptible than those grown under low nitrate (0.1 mM) and ammonium (5 mM) in the Arabidopsis-Alternaria brassicicola pathosystem. However, it is not known how seedling metabolism is modulated by nitrogen nutrition, nor what is its response to pathogen infection. Here, we addressed this question using the same pathosystem and nutritive conditions, examining germination kinetics, seedling development, but also shoot ion contents, metabolome, and selected gene expression. Nitrogen nutrition clearly altered the seedling metabolome. A similar metabolomic profile was observed in inoculated seedlings grown at high nitrate levels and in not inoculated-seedlings. High nitrate levels also led to specific gene expression patterns (e.g., polyamine metabolism), while other genes responded to inoculation regardless of nitrogen supply conditions. Furthermore, the metabolites best correlated with high disease symptoms were coumarate, tyrosine, hemicellulose sugars, and polyamines, and those associated with low symptoms were organic acids (tricarboxylic acid pathway, glycerate, shikimate), sugars derivatives and β-alanine. Overall, our results suggest that the beneficial effect of high nitrate nutrition on seedling susceptibility is likely due to nutritive and signaling mechanisms affecting developmental plant processes detrimental to the pathogen. In particular, it may be due to a constitutively high tryptophan metabolism, as well as down regulation of oxidative stress caused by polyamine catabolism.
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Oshima, Chiaki, Yuji Tokumoto, and Michiko Nakagawa. "Biotic and abiotic drivers of dipterocarp seedling survival following mast fruiting in Malaysian Borneo." Journal of Tropical Ecology 31, no. 2 (2014): 129–37. http://dx.doi.org/10.1017/s026646741400073x.
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Abstract:South-East Asian tropical rain forests experience sporadic, but profuse, seed production after general flowering, leading to the synchronous emergence of various seedlings and subsequent seedling dynamics, which play a crucial role in determining species distribution and coexistence. We examined the relative importance of both biotic (initial height, conspecific seedling density) and abiotic (canopy openness, per cent sand, soil water content) drivers using survival data for 1842 seedlings of 12 dipterocarp species for 1.5 y following mast fruiting in an old-growth Bornean tropical rain forest. More than 30% of all dipterocarp seedlings survived 1.5 y after mast fruiting. When all species were analysed together, we found that initial seedling height, canopy openness and conspecific seedling density affected dipterocarp seedling survival. Negative density dependence indicated that predators were not satiated, but dipterocarp seedlings rather suffered from host-specific natural enemies or intraspecific competition. Species-level analyses of seven dipterocarp species showed large variation in response to biotic and abiotic factors. These results suggest that interspecific differences in the relative importance of biotic and abiotic effects on seedling survival might contribute to species coexistence.
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Morris, D. M., G. B. MacDonald, and K. M. McClain. "Evaluation of morphological attributes as response variables to perennial competition for 4-year-old black spruce and jack pine seedlings." Canadian Journal of Forest Research 20, no. 11 (1990): 1696–703. http://dx.doi.org/10.1139/x90-226.
Full textAbstract:
The sensitivity of seedling morphological attributes to changing competition levels was evaluated on 4-year-old black spruce (Piceamariana (Mill.) B.S.P.) and jack pine (Pinusbanksiana Lamb.) seedlings to determine the most appropriate response variables to be used in the assessment of early plantation performance. A total of 720 seedlings (360 per species) were sampled between 1987 and 1989, covering a range of stock types, soil textures, and competition levels. A competition index, derived from hemispherical photographs, provided an estimate of incident radiation received by each sampled seedling. Seedling stem volume at time of planting was used as a covariate in the regression analyses. Stratification by plantation was done to account for variations in site quality. The results from this study demonstrated that total height or current height increment were not reliable for quantifying individual seedling response to inter specific competition for 4-year-old black spruce or jack pine plantations. Overall, the most consistent response variable was total seedling dry weight. Coefficients of determination ranged from 0.116 to 0.534 for black spruce and from 0.601 to 0.810 for jack pine across the range of sites and stock types. If it is inappropriate to determine total seedling dry weight, root collar diameter would be the best substitute. Correlation coefficients between these two variables were 0.897 for black spruce and 0.912 for jack pine.
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Chanway, C. P., and F. B. Holl. "Influence of soil biota on Douglas-fir (Pseudotsuga menziesii) seedling growth: the role of rhizosphere bacteria." Canadian Journal of Botany 70, no. 5 (1992): 1025–31. http://dx.doi.org/10.1139/b92-127.
Full textAbstract:
The influence of soil biota on Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedling growth was investigated by sowing seed collected from two ecologically distinct zones in British Columbia, Chilliwack and Williams Lake, in soil collected from the same two areas. Seedling biomass of both Douglas-fir ecotypes was greatest in unpasteurized soil collected from the same area as was the seed, but pasteurization negated this effect. In addition, Chilliwack seedlings responded specifically to biota present only in Chilliwack soil. To determine if rhizosphere bacteria were involved in these growth responses, bacteria were isolated from the rhizosphere of wild Douglas-fir seedlings collected from both locations, and putative growth promoting bacteria were selected in a screening experiment. Selected bacteria were then tested for seedling growth response specificity using a factorial design in which seed, soil, and bacteria from both locations were evaluated in all combinations. Inoculation of Douglas-fir seed with some of the selected bacterial isolates increased seedling biomass in pasteurized soil to a level similar to that of seedlings grown in unpasteurized soil, but there was no evidence that adaptive relationships involving bacteria, Douglas-fir, and the soil in which they naturally grew were important in effecting seedling growth promotion. However, Douglas-fir shoot biomass increased 39% and root biomass 68% after bacterial inoculation in some treatment combinations involving pasteurized soil. Key words: Douglas-fir seedlings, growth, rhizosphere bacteria.
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Healy, Will, and David Graper. "PETUNIA SEEDLING GROWTH - FLOWERING RESPONSE." HortScience 25, no. 9 (1990): 1103a—1103. http://dx.doi.org/10.21273/hortsci.25.9.1103a.
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Petunia `Red Flash' seedlings were grown under HPS (175 μmol m-2 s-1) photoperiod treatments of 10, 12, 14 or 16 hr at 20C soil temperature in a shaded glasshouse where the maximum peak PPF was reduced to 150 μmolm-2s-1. Seedling were transplanted after they had unfolded a specific number of leaves and grown under natural days or placed under photoperiod treatments which consisted of an 8 hr natural day with incandescent day extension treatments of 1 to 6 hours.A 16 hr HPS treatment decreased the days to transplant (DTT) by more than 4 days and reduced the days from transplant to flower (DTF) by more than 5 days. The total reduction in days from sowing to flower (DSTF) was at least 8 days. When compared to unlighted controls, the reduction in DSTF was 26 days. The longer the seedlings remained under the HPS treatments, the shorter the DTF and DSTF. Premature shifting of plants to natural days resulted in up to a 9 day delay in DSTF. At photoperiods greater than 13 hr, the number of nodes subtending the inflorescence becomes constant regardless of number of leaves at transplant.
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Jefferson, P., and R. Muri. "Competition, light quality and seedling growth of Russian wildrye grass (Psathyrostachys juncea)." Acta Agronomica Hungarica 55, no. 1 (2007): 49–60. http://dx.doi.org/10.1556/aagr.55.2007.1.6.
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The low seedling vigour of Russian wildrye grass ( Psathyrostachys juncea ) (RWR) limits its use. Shading from durum wheat ( Triticum turgidum ) reduced RWR leaf number, tiller number, leaf area and seedling dry weight in a growth room experiment. Treatments with similar shading differed in tiller number and dry weight, which suggested that light quality may have also contributed to these responses. In a second growth room experiment, light intensity (PAR) and red:far-red light ratio (670:730 nm) were altered by coloured plastic filters suspended above seedlings of Russian wildrye, crested wheatgrass ( Agropyron desertorum ) (CWG) and Dahurian wildrye grass ( Elymus dahuricus ) (DWR). Leaf area, tiller number and dry weight of RWR seedlings were reduced by declining red:far-red light ratio while light intensity differences at similar red:far-red ratio did not affect these variables. CWG exhibited similar responses to declining red:far-red light ratio as RWR, except that it exhibited a seedling weight response to light intensity. DWR tiller number was not responsive to low red:far-red light ratio but rather to low light intensity. However, DWR seedling weight, tiller weight and leaf area were responsive to declining red:far-red light ratio. These results indicate that RWR seedlings are sensitive to light quality changes caused by neighbouring plants.
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Peng, Zehui, Fazhan Yang, Yuhuan Li, Xiang Li, Baogang Li, and Guoli Xu. "Design and Testing of a Whole-Row Top-Loosening Stem-Clamping Seedling Extraction Device for Hole Tray Seedlings." Agriculture 15, no. 2 (2025): 165. https://doi.org/10.3390/agriculture15020165.
Full textAbstract:
A combined seedling extraction device was developed that operates by first top loosening and then clamping the stem in order to solve the current issues with automated transplanting technology, such as low seedling extraction efficiency and a high rate of substrate loss. The pepper plug tray seedlings were selected as the experimental subjects for testing the mechanical properties of the stems. The tensile and compressive mechanical properties of the stems were obtained, and the kinematic model of the seedling spacing process and the mechanical model of the seedling clamping process were established. Key parameters of the seedling extraction device were analyzed and calculated, and an automated seedling extraction system was constructed. Using substrate moisture content, seedling age, and extraction frequency as experimental factors, orthogonal tests were conducted. Through variance analysis and 3D response surface analysis, the optimal rounded parameter values were determined: 48% substrate moisture content, 38-day-old seedlings, and a seedling extraction frequency of 60 plants/min. Under these conditions, the seedling extraction success rate was 94.44%, the substrate loss rate was 6.07%, and the seedling damage rate was 4.17%, meeting the requirements for automated seedling extraction.
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Zhang, Haiyan. "Seed Germination and Early Seedling Growth of Cynanchum bungei Decne (Asclepiadaceae) in Response to Photoperiod, Temperature, and Seed Size." HortScience 47, no. 9 (2012): 1338–41. http://dx.doi.org/10.21273/hortsci.47.9.1338.
Full textAbstract:
Cynanchum bungei Decne is a rare, endemic, and important medicinal plant species in China. Seed germination and early seedling growth of large seeds (greater than 7 mm) and small seeds (smaller than 7 mm) were investigated at three temperatures (15, 20, and 25 °C) in both continuous light and alternating light/dark photoperiods to determine seed propagation requirements. Photoperiod significantly affected seed germination and early seedling growth. Germination and seedling growth at a 12:12-h photoperiod performed better than in continuous light. Temperature had a significant effect on germination index (GI), vigor index (VI), germination velocity (GV), mean germination time (MGT), shoot biomass (SB), root biomass (RB), and taproot length (TL), but no significant effect on final germination percentage (FGP). A temperature of 20 °C was the optimum temperature for seed germination and early seedling growth. Average growth height (AGH) and relative growth rate (RGR) of shoots at 15 °C were greater than that at 20 °C. Large seeds had better germination and seedling performance than small seeds. However, small-seeded seedlings had greater biomass allocated to roots (BAR) and root-to-seedling ratio (RSR) than seedlings from large seeds. Small seeds of C. bungei could be more competent in unfavorable soil and light conditions than large seeds.
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Jones, Robert H., Ralph D. Nyland, and Dudley J. Raynal. "Response of American Beech Regeneration to Selection Cutting of Northern Hardwoods in New York." Northern Journal of Applied Forestry 6, no. 1 (1989): 34–36. http://dx.doi.org/10.1093/njaf/6.1.34.
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Abstract Root sprout and seedling regeneration of American beech was sampled in two maple-dominated northern hardwood stands 13-14 years after single-tree selection cutting. The largest stems had been advance regeneration, and seedlings comprised a substantial and well-distributed portion of these. Among stems established after the cut, root sprouts outnumbered seedlings. Total beech regeneration abundance was correlated with basal area of overstory beech. For long-term beech control, it may be useful to reduce beech seedling populations before selection cutting, and to cut large diameter beech trees. North. J. Appl. For. 6:34-36, March 1989.
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Santos, Gildomar Alves dos, David Francis Robert Philip Burslem, Milton Serpa de Meira Jr, and Stanislau Parreira Cardozo. "Introduction of native tree species into degraded Cerrado vegetation." Interação 21, no. 2 (2021): 61–84. http://dx.doi.org/10.53660/inter-102-s127.
Full textAbstract:
Experimental restoration using tree seedlings is a common strategy for accelerating succession on degraded post-agricultural land formerly occupied by Cerrado vegetation. Seedling growth in degraded tropical lands is constrained by various factors. The goal of this study was to evaluate the seedling growth and survival of seven native tree species used to accelerate forest recovery in a gully area with stressful environmental conditions. The experimental design involved fenced and unfenced blocks, presence and absence of fertilization and use of an adhesive to prevent ant herbivory (four treatments with four replicates). Seedlings were planted in December 2006 and collection of data on seedling basal diameter, height, mortality and herbivory started on January 24th 2007 and continued every three months, until final data collection on January 31st 2009 (9 measurement dates). Overall seedling survival was 38 % and protecting seedlings did not influence growth, but seedlings grew faster in response to the addition of fertilizer containing N, P and K. The use of the adhesive Tanglefoot to exclude leaf cutter ants had no influence on growth. Fencing reduced seedling mortality, but combining fencing with Tanglefoot did not. Nutrient availability limits seedling growth and survival in the gully. Direct planting of seedlings of native trees may accelerate succession in degraded Cerrado lands subject to interventions that overcome constraints on seedling growth and survival.
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Flasiński, Stanisław, Janina Rogozińska, and Lucyna Drozdowska. "The effect of phosphours and water deficit on phosphatase activity and proline accumulation in seedling cotyledons and roots of oilseed rape as compared to that of excised cotyledons and roots." Acta Societatis Botanicorum Poloniae 55, no. 1 (2014): 83–96. http://dx.doi.org/10.5586/asbp.1986.010.
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Oilseed rape seedlings and excised cotyledons and roots were exposed to phosphorus and osmotic stress (-1 MPa: NaCl or PEG). The stress factors limited the growth of the seedlings and inhibited the growth of the excised roots and cotyledons. The phosphorus content in the cotyledons and roots depended on its level in the media and on the stress factors used. Phosphorus deficiency differentiated total phosphatase activity in seedling cotyledons and increased the activity in the excised cotyledons. In the excised and seedling roots, the lack of phosphorus, its deficiency and stress imposed by the addition of NaCl, caused an increase in total and specific phosphatase activity. Osmotic stress caused proline accumulation in both the seedling and excised cotyledons, but the effect of phosphorus stress was much smaller. Proline increase in seedling roots followed only after the osmotic stress caused by NaCl. The proline content in the excised roots was low. Stress factors lowered the protein content in the seedling and excised cotyledons. In both seedling and excised roots, the lowering of the protein content occurred mainly in response to osmotic stress. Kinetin modified metabolic responses in seedling cotyledons and roots. The use of in vitro culture allowed the elucidation of the tested responses. In excised cotyledons grown under stress conditions, kinetin increased the phosphorus and protein contents and lowered proline accumulation, suggesting that kinetin had the ability to overcome phosphorus and osmotic stress. The excised oilseed rape roots responded only slightly to kinetin (Drozdowska and Rogozińska 1984) and its effect was much smaller.
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Dong, Liqiang, Tiexin Yang, Rui Li, Liang Ma, Yingying Feng, and Yuedong Li. "Grain Yield, Rice Seedlings and Transplanting Quantity in Response to Decreased Sowing Rate under Precision Drill Sowing." Agriculture 14, no. 10 (2024): 1745. http://dx.doi.org/10.3390/agriculture14101745.
Full textAbstract:
Mechanical transplanting has become an important part of modern Chinese rice production, and an inadequate sowing rate severely inhibits rice seedling growth and development. Precision drill sowing is an effective method for obtaining higher quality seedlings during machine transplanting. There is a lack of systematic research on the precision drilling of rice. Therefore, we carried out research on the quality of machine-transplanted seedlings and precision drill sowing transplantation. A greenhouse experiment (Liaoning Rice Research Institute) and field experiment (Sujiatun District, Shenyang City, Liaoning Province, China) were conducted between 2020 and 2021 to analyze the influence of precision drill sowing on rice growth and yield. Precision drill sowing was conducted at four sowing rates (3400, 3600, 3800, and 4000 seeds/tray), and traditional broadcasting was also conducted at a sowing rate of 4000 seeds/tray. We evaluated the seedling rice quality, physiological and biochemical characteristics and transplanting quantity. The results indicated that precision drill sowing at a sowing rate of 3400 seeds/tray resulted in the highest plumpness value (0.18) and seedling strength index (0.42) of individual plants. However, the empty hill rate was as high as 3.05%, which did not satisfy the field seedling number requirement. Precision drill sowing at a sowing rate of 4000 seeds/tray resulted in the lowest physiological (the average levels of SOD, POD and soluble protein were 311.78 µg/g, 8.25 µg/g and 1.28 µg/g) and biochemical indices of individual plants. The damaged seedling rate increased by 2.07%, and the dead seedling rate increased by 0.25%, resulting in poor seedling and transplanting quality. In this study, 3800 seeds/tray was the best option and had the highest yields of 10,776.60 kg/ha and 10,730.85 kg/ha over the two years. This sowing approach performs well in terms of field transplanting, provides a balance point between seedling number and quality and is conducive to rice yield production. The results of this study are important for improving rice seedling quality, enhancing field transplanting quantity and increasing rice yield and food security.
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Luo, Yonghong, Jinfeng Zhang, Xingfu Yan, et al. "Response of Seedling Growth Characteristics to Seed Size and Cotyledon Damage in Quercus wutaishanica." Forests 14, no. 9 (2023): 1905. http://dx.doi.org/10.3390/f14091905.
Full textAbstract:
The successful establishment of seedlings is very important for plant regeneration, but it is vulnerable to many factors at this stage. Cotyledon damage will directly affect the health of seedlings, thus affecting the regeneration of the plant population. However, little is known about the effects of different cotyledon loss degrees of large and small seeds on seedling growth. We investigated the effects of 1/4 (light excision), 1/2 (moderate excision), and complete excision of cotyledons (heavy excision) on the growth characteristics of seedlings germinating from different sizes of seeds. The results showed that (1) shoot height, basal stem diameter, number of leaves, leaf area per plant, specific leaf area, and biomass were significantly higher in large-seeded seedlings than in small-seeded seedlings; (2) slight cotyledon excision had no effect on the biomass of large-seeded seedlings but significantly reduced the biomass of small-seeded seedlings. Our study highlights that large-seeded seedlings are more tolerant than small-seeded seedlings in the early seedling recruitment, suggesting that large-seeded seedlings have a strong fitness for recruitment in young populations of Q. wutaishanica.
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Wahyuningtyas, R. S., J. Junaidah, and P. B. Santosa. "Response of Ficus variegata seedling size on their early growth in imperata grassland." IOP Conference Series: Earth and Environmental Science 959, no. 1 (2022): 012012. http://dx.doi.org/10.1088/1755-1315/959/1/012012.
Full textAbstract:
Abstract Ficus variegata is pioneer species that provides pulp raw materials, soil water protection, beehives tree, animal fodder, and medicinal plants. Introduction of F. variegata seedling at Imperata grassland constrained with low plant survival which caused by stressed plants and stagnant growth. The objective of this research was to determine the effect of five F. variegata seedlings size on the initial growth at Imperata grassland. The research was used Randomized Complete Block Design, with 5 seedling sizes for the treatment, there are size A (seedling height 15-50 cm), size B (51-75 cm), size C (76-100 cm), size D (101-125 cm), and size E (126-150 cm). In this research, we observe some parameters like height and stem diameter increment, canopy width, and plant survival at 1, 6, and 12 months old. Different seedling size has a very significant effect at six months old and very significant effect at 12 months old on the height, diameter and width crown increment. Seedling size 15-50 cm has shown faster height growth but has lower survival than another size in the dry season. For rehabilitation Imperata grassland, it is recommended using seedling size 50-125 cm because more adaptive and shown better growth in all parameters.
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McGuire, John P., Robert J. Mitchell, E. Barry Moser, Stephen D. Pecot, Dean H. Gjerstad, and Craig W. Hedman. "Gaps in a gappy forest: plant resources, longleaf pine regeneration, and understory response to tree removal in longleaf pine savannas." Canadian Journal of Forest Research 31, no. 5 (2001): 765–78. http://dx.doi.org/10.1139/x01-003.
Full textAbstract:
Resource availability and planted longleaf pine (Pinus palustris Mill.) seedling and understory vegetation response within and among three sizes of experimentally created canopy gaps (0.11, 0.41, 1.63 ha) in a mature longleaf pine savanna were investigated for 2 years. Longleaf pine seedlings and understory vegetation showed increased growth in gaps created by tree removal. Longleaf pine seedling growth within gaps was maximized approximately 18 m from the uncut savanna. Increased longleaf pine seedling survival under the uncut savanna canopy observed after the first year suggests that the overstory may facilitate establishment of longleaf pine seedlings rather than reduce survival through competition. Despite the relative openness of the uncut longleaf pine forest, light quantity was increased by tree removal. Light was also the resource most strongly correlated with seedling and understory vegetation growth. Although net N mineralization was correlated to seedling response, the amount of variation explained was low relative to light. Belowground (root) gaps were not strong, in part because of non-pine understory roots increasing in biomass following tree removal. These results suggest that regeneration of longleaf pine may be maximized within gap sizes as small as approximately 0.10 ha, due largely to increases in light availability.
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Wood, Katherine E. A., Richard K. Kobe, Inés Ibáñez, and Sarah McCarthy-Neumann. "Tree seedling functional traits mediate plant-soil feedback survival responses across a gradient of light availability." PLOS ONE 18, no. 11 (2023): e0293906. http://dx.doi.org/10.1371/journal.pone.0293906.
Full textAbstract:
1. Though not often examined together, both plant-soil feedbacks (PSFs) and functional traits have important influences on plant community dynamics and could interact. For example, seedling functional traits could impact seedling survivorship responses to soils cultured by conspecific versus heterospecific adults. Furthermore, levels of functional traits could vary with soil culturing source. In addition, these relationships might shift with light availability, which can affect trait values, microbe abundance, and whether mycorrhizal colonization is mutualistic or parasitic to seedlings. 2. To determine the extent to which functional traits mediate PSFs via seedling survival, we conducted a field experiment. We planted seedlings of four temperate tree species across a gradient of light availability and into soil cores collected beneath conspecific (sterilized and live) and heterospecific adults. We monitored seedling survival twice per week over one growing season, and we randomly selected subsets of seedlings to measure mycorrhizal colonization and phenolics, lignin, and NSC levels at three weeks. 3. Though evidence for PSFs was limited, Acer saccharum seedlings exhibited positive PSFs (i.e., higher survival in conspecific than heterospecific soils). In addition, soil microbes had a negative effect on A. saccharum and Prunus serotina seedling survival, with reduced survival in live versus sterilized conspecific soil. In general, we found higher trait values (measured amounts of a given trait) in conspecific than heterospecific soils and higher light availability. Additionally, A. saccharum survival increased with higher levels of phenolics, which were higher in conspecific soils and high light. Quercus alba survival decreased with higher AMF colonization. 4. We demonstrate that functional trait values in seedlings as young as three weeks vary in response to soil source and light availability. Moreover, seedling survivorship was associated with trait values for two species, despite both drought and heavy rainfall during the growing season that may have obscured survivorship-trait relationships. These results suggest that seedling traits could have an important role in mediating the effects of local soil source and light levels on seedling survivorship and thus plant traits could have an important role in PSFs.
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Kim, Hyeonji, Heejae Jo, Gwang-Jung Kim, Hyung-Sub Kim, and Yowhan Son. "Effects of Spring Warming and Drought Events on the Autumn Growth of Larix kaempferi Seedlings." Water 14, no. 12 (2022): 1962. http://dx.doi.org/10.3390/w14121962.
Full textAbstract:
High temperatures and droughts following winter dormancy can negatively affect seedling growth and mortality. An open-field experiment was conducted to study the growth and mortality of Larix kaempferi seedlings in response to spring warming and drought treatments and to determine whether seedlings could regain their growth capability once the treatments were discontinued. In May 2020, 1-year-old seedlings were exposed to four treatments: control, warming-only, drought-only, and the combined warming and drought. Drought treatment reduced the seedling height and root collar diameter and increased the mortality rate. The combined warming and drought treatments had the highest mortality rates, followed by the drought, control, and warming treatments. However, after the cessation of the treatments, the combined warming and drought treatments increased seedling height, root collar diameter, and individual seedling biomass because the high mortality rate relaxed competition among seedlings. This suggests that the effects of low competition on the surviving seedlings may mitigate the negative effects of warming and drought on seedling growth. Our study demonstrates that despite the high mortality and decreased growth during the treatment period, seedlings subjected to combined high temperature and drought stress showed short-term high levels of growth compared to seedlings subjected to a single stress.
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Rosner, Lee S., and Robin Rose. "Synergistic stem volume response to combinations of vegetation control and seedling size in conifer plantations in Oregon." Canadian Journal of Forest Research 36, no. 4 (2006): 930–44. http://dx.doi.org/10.1139/x05-292.
Full textAbstract:
There are few published studies examining the effects of the interaction of seedling size and vegetation control on the growth of Pacific Northwest conifer species. Data from two vegetation management studies encompassing five planting sites, four conifer species, and two stock types were analyzed to determine the relative effects of seedling size at planting and intensity of vegetation control on subsequent seedling growth. Study 1 tested eight combinations of annual broadcast weed control or no weed control applied over the course of 5 years. Study 2 tested spot herbicide applications of differing area, as well as herbaceous-only and woody-only control treatments. The effect of seedling size was determined by analysis of covariance, with basal diameter as the covariate. Both seedling size and weed control increased growth of all conifer species through 4, 5, or 12 years, but responses varied by species and site. Diameter and height responses to weed control and seedling size were additive, whereas volume differences between treatments increased with increasing seedling size. The implication for management is that the volume return from increased weed control is maximized by planting the largest possible seedlings; conversely, the volume from increased seedling size is maximized at the highest weed control intensities.
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Youngblood, Andrew, Elizabeth Cole, and Michael Newton. "Survival and growth response of white spruce stock types to site preparation in Alaska." Canadian Journal of Forest Research 41, no. 4 (2011): 793–809. http://dx.doi.org/10.1139/x11-001.
Full textAbstract:
To identify suitable methods for reforestation, we evaluated the interacting effects of past disturbance, stock types, and site preparation treatments on white spruce (Picea glauca (Moench) Voss) seedling survival and growth across a range of sites in Alaska. Replicated experiments were established in five regions. At each site, two complete installations differed in time since disturbance: “new” units were harvested immediately before spring planting and “old” units were harvested at least 3 years before planting. We compared mechanical scarification before planting, broadcast herbicide application during the fall before planting, and no site preparation with 1-year-old container-grown seedlings from two sources, 2-year-old bare-root transplants from two sources, and 3-year-old bare-root transplants. Seedlings were followed for 11 years on most sites. Based on meta-analyses, seedling survival increased 10% with herbicide application and 15% with mechanical scarification compared with no site preparation. Scarification and herbicide application increased seedling height by about 28% and 35%, respectively, and increased seedling volume by about 86% and 195%, respectively, compared with no site preparation. Soil temperature did not differ among site preparation methods after the first 7 years. Results suggest that white spruce stands may be successfully restored through a combination of vegetation control and use of quality planting stock.
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Chauhan, Bhagirath Singh. "Weedy rice (Oryza sativa) II. Response of Weedy Rice to Seed Burial and Flooding Depth." Weed Science 60, no. 3 (2012): 385–88. http://dx.doi.org/10.1614/ws-d-11-00213.1.
Full textAbstract:
Weedy rice is a serious problem of cultivated rice in most of the rice-growing areas in Asia, causing increased production costs and yield losses in rice. A study was conducted to determine the response of weedy rice accessions from India (IWR), Malaysia (MWR), Thailand (TWR), and Vietnam (VWR) to seed burial and flooding depths. The greatest emergence for each weedy rice accession (97% for IWR, 82% for MWR, 97% for TWR, and 94% for VWR) was observed in seeds placed on the soil surface. Seedling emergence decreased with increase in burial depth. For the IWR accession, 0.5% of the seedlings emerged from 8-cm depth, whereas for the other three weedy rice accessions, no seedlings emerged from this depth. When seeds were sown on the soil surface, flooding depth ranging from 0 to 8 cm had no or very little effect on seedling emergence of different weedy rice accessions. On the other hand, flooding decreased seedling emergence in all weedy rice accessions when seeds were sown at 1 cm deep into the soil. Compared with seedling emergence, flooding had a more pronounced effect on seedling biomass for all weedy rice accessions. A flooding depth of 2 cm reduced seedling biomass by an amount greater than 85% of each weedy rice accession. The results of this study suggest that emergence and growth of weedy rice could be suppressed by deep tillage that buries seeds below their maximum depth of emergence (i.e., > 8 cm for the accessions studied) and by flooding fields as early as possible. The information gained from this study may help design cultural management strategies for weedy rice in Asia.
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Liptay, Albert, and Diane Edwards. "Tomato Seedling Growth in Response to Variation in Root Container Shape." HortScience 29, no. 6 (1994): 633–35. http://dx.doi.org/10.21273/hortsci.29.6.633.
Full textAbstract:
Roots of tomato (Lycopersicon esculentum Mill.) seedlings grown in multicelled trays were confined largely to the interface between the growing medium and the inner surface of the cell. Because of the predominance of roots in this area, experiments were done in prototype cells to relate seedling growth to change in this interface area while retaining a constant volume. The cell shapes that were tested included a square cell with 1.36-cm sides and other rectangular cells. All cells were 3 cm in height, but widths decreased incrementally by 0.1 cm from the 1.36×1.36-cm square to rectangles with inner cell dimensions of 0.36×5.14 cm. With these changing shapes, the interface area increased but cell width decreased to a more narrow cell. Seedling height increased as the cell shape was changed from a square (1.36 × 1.36 cm) to an elongated rectangle (1.74 × 1.06 cm). More narrow cells caused seedling height to decrease; the shortest seedlings occurred in 0.36 × 5.14-cm cells. Root growth was unaffected by change in cell shape. The smoothness of the inner cell surface, however, affected root growth; a rough texture resulted in stubby and reduced root growth but had no effect on shoot growth.
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Groninger, J. W., J. R. Seiler, S. M. Zedaker, and P. C. Berrang. "Photosynthetic response of loblolly pine and sweetgum seedling stands to elevated carbon dioxide, water stress, and nitrogen level." Canadian Journal of Forest Research 26, no. 1 (1996): 95–102. http://dx.doi.org/10.1139/x26-010.
Full textAbstract:
Seedling stands of loblolly pine (Pinustaeda L.) and sweetgum (Liquidambarstyraciflua L.) were grown in monoculture or mixed stands for two growing cycles in controlled-environment chambers. Treatments consisted of ambient (408 ppm) and elevated (806 ppm) CO2, concentrations, water-stressed and well-watered conditions, and low (20 kg N/ha) and high (215 kg N/ha) nitrogen application rates. Photosynthesis rates were measured under ambient and elevated cuvette CO2 concentrations for both whole stands and individual seedlings from these stands. Significant interactions between CO2 and water suggested that elevated CO2 concentration compensated for low water availability in individually measured loblolly pine and in whole seedling stands regardless of stand type. Expressing photosynthesis on a soil area versus a leaf-mass basis influenced the photosynthetic rankings of the three stand types relative to one another. Net photosynthetic rates per unit leaf mass were 390 and 880% higher in individually measured seedlings than in whole monoculture stands for loblolly pine and sweetgum, respectively. Lower photosynthetic contributions from lower canopy leaves in whole seedling stands compared with the upper canopy leaves used in individual-seedling measurements were thought to be responsible for lower photosynthetic rates in seedling stands. These results suggest that photosynthetic response is influenced by canopy dynamics that are unaccounted for by individual-seedling measurements of photosynthesis. Differences in photosynthetic response between loblolly pine and sweetgum stands and individuals are thought to be largely due to species-specific differences in canopy light extinction characteristics.
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Zhang, Jianhua, and Paul B. Cavers. "Seedling emergence after maternal bentazon application to 10 cocklebur (Xanthium strumarium) populations." Canadian Journal of Plant Science 74, no. 4 (1994): 863–66. http://dx.doi.org/10.4141/cjps94-157.
Full textAbstract:
Maternal environments have been reported to affect various seed and seedling characteristics in many plants. In this study, we examined the effect of bentazon application to the mother plants on seed germination and seedling emergence of 10 cocklebur populations from wetlands or cultivated land. The mortality or longevity of fully developed seeds was affected significantly by bentazon application. Rate of seedling emergence showed little response, whereas percentage seedling emergence and percentage viable seeds in the soil were reduced by bentazon treatment to the mother plants. Populations from wetlands produced seedlings earlier than those from cultivated land. Key words: Seedling emergence, seed bank, herbicide, bentazon, cocklebur, Xanthium strumarium
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Möhler, Henrike, Tim Diekötter, Geeltje Marie Bauer, and Tobias W. Donath. "Conspecific and heterospecific grass litter effects on seedling emergence and growth in ragwort (Jacobaea vulgaris)." PLOS ONE 16, no. 2 (2021): e0246459. http://dx.doi.org/10.1371/journal.pone.0246459.
Full textAbstract:
Jacobaea vulgaris Gaertn. or common ragwort is a widespread noxious grassland weed that is subject to different regulation measures worldwide. Seedling emergence and growth are the most crucial stages for most plants during their life cycle. Therefore, heterospecific grass or conspecific ragwort litter as well as soil-mediated effects may be of relevance for ragwort control. Our study examines the effects of conspecific and heterospecific litter as well as ragwort conditioned soil on seedling emergence and growth. We conducted pot experiments to estimate the influence of soil conditioning (with, without ragwort), litter type (grass, ragwort, grass-ragwort-mix) and amount (200 g/m², 400 g/m²) on J. vulgaris recruitment. As response parameters, we assessed seedling number, biomass, height and number of seedling leaves. We found that 200 g/m² grass litter led to higher seedling numbers, while litter composed of J. vulgaris reduced seedling emergence. Litter amounts of 400 g/m² had negative effects on the number of seedlings regardless of the litter type. Results for biomass, plant height and leaf number showed opposing patterns to seedling numbers. Seedlings in pots treated with high litter amounts and seedlings in ragwort litter became heavier, grew higher and had more leaves. Significant effects of the soil conditioned by ragwort on seedling emergence and growth were negligible. The study confirms that the amount and composition of litter strongly affect seedling emergence and growth of J. vulgaris. Moreover, while conspecific litter and high litter amounts negatively affected early seedling development in ragwort, those seedlings that survived accumulated more biomass and got taller than seedlings grown in heterospecific or less dense litter. Therefore, ragwort litter has negative effects in ragwort germination, but positive effects in ragwort growth. Thus, leaving ragwort litter on pastures will not reduce ragwort establishment and growth and cannot be used as management tool.
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M.B. Areza-Ubaldo, S.S. Magat, E.P. Rillo, and M.I. Secretaria. "Crop nutrition and fertilizer management of embryo-cultured seedlings of Makapuno and Laguna Tall coconuts with special reference to their response to different levels of NaCl and chicken manure." CORD 22, no. 2 (2006): 14. http://dx.doi.org/10.37833/cord.v22i2.170.
Full textAbstract:
A two-year nursery study of embryo-cultured Laguna Tall (ECLAGT) and embryo-cultured Makapuno Tall (ECMAKT) coconut seedlings was conducted at the Philippine Coconut Authority - Albay Research Center, Guinobatan, Albay aimed to know the effects of applying different levels of sodium chloride (NaCl) (common table salt) and chicken manure (CM) on the vegetative growth and leaf nutrient status of the seedlings. The soil used in the study is a volcanic ash- rich Guinobatan silt loam, classified as Entic Dystrandept soil subgroup (U.S. Soil Taxonomy/Classification).
 EC seedlings with the application of NaCl at a total dose of 18-54 g/seedling and chicken manure at 250-750 g/seedling, applied within the 12-month nursery (at intervals of 2,4,6,8,10 months) significantly produced taller seedlings with bigger girth and more total living fronds than the unfertilized ECLAGT and ECMAKT seedlings. The levels of nutrient application (fertilization) on EC seedlings is clearly much lower than that of the average rates used in growing ordinary seedlings from seednuts, i.e. seedling with embryo attached to the whole nut in the nursery.
 The better growth of ECLAGT and ECMAKT seedlings in terms of their girth, plant height and total living fronds produced was significantly associated with higher or very satisfactory levels of leaf N, P, K, Cl, Ca, Na, Mg, S, B, and Fe (leaf #4 of 12-month old EC seedlings).
 The overall results clearly indicate the practical need to apply a combination of sodium chloride and dried chicken manure, even at moderate rates (total) of 18 g/seedling and 250 g/seedling respectively, divided equally during the 12-month nursery stage for normal growth and proper nutrition of EC seedlings. This recommended fertilization management practice should ensure healthy and good quality ECMAKT seedlings as planting materials.
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Ketter, Benjamin L., and Ricardo M. Holdo. "Strong competitive effects of African savanna C4 grasses on tree seedlings do not support rooting differentiation." Journal of Tropical Ecology 34, no. 1 (2018): 65–73. http://dx.doi.org/10.1017/s0266467418000020.
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Abstract:Rooting differentiation between established trees and grasses has been well documented in savannas, but it remains unclear to what extent tree-grass rooting differences affect competition between newly established seedlings and grasses. To examine this question, a greenhouse experiment was conducted at the University of Missouri, USA. Twenty 3-mo-old seedlings each of two African savanna tree species (Acacia nigrescens and Colophospermum mopane) were grown for 8 mo with two crossed factors: grass competition and irrigation depth. Strong negative effects of grass competition on final seedling biomass and leaf photosynthetic and stomatal conductance occurred in both tree species, but no effects of irrigation depth were detected. There was a clear tree species by grass competition interaction, suggesting interspecific variation in competitive response. The results emphasize the importance of below-ground competition with grasses for physiological and morphological responses of tree seedlings, while minimizing the importance of tree-grass rooting depth differences as a factor in modulating the competitive response of trees to grasses at the seedling stage.
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Tian, Chengjun. "Chinese Cabbage Transplanter." Advances in Engineering Technology Research 12, no. 1 (2024): 804. https://doi.org/10.56028/aetr.12.1.804.2024.
Full textAbstract:
In response to the problems encountered during the transplanting of Chinese cabbage seedlings, a Chinese cabbage transplanter suitable for farmers has been designed and produced. The main functions of the Chinese cabbage transplanter include seedling transportation, seedling delivery, and seedling planting. Firstly, by designing a specially designed seedling tray, the accurate continuous transportation of individual Chinese cabbage seedlings can be achieved. Then, the Chinese cabbage seedlings are transported to the planting location through a planetary gear mechanism. Finally, the Chinese cabbage seedlings are inserted into the soil wrapped in mechanical claws to complete planting. The team also analyzed and calculated the key components: the planting device, opening and closing device, and seedling conveying device. On this basis, the detailed mechanical structure design was implemented. After the selection and design of the power and control mode of the transplanter, the trial production and testing of the prototype were completed. Featuring high automation, simple operation, low cost, flexible and diverse application scenarios, and adaptability to different farming methods in various regions, the transplanter can be used for self-employed greenhouse planting. After further modification, it can also be used for large-scale planting with a high value of popularization and application.
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Šņepste, Ilze, Baiba Krivmane, Vilnis Šķipars, Astra Zaluma, and Dainis E. Ruņģis. "Induction of Defense Responses in Pinus sylvestris Seedlings by Methyl Jasmonate and Response to Heterobasidion annosum and Lophodermium seditiosum Inoculation." Forests 12, no. 5 (2021): 628. http://dx.doi.org/10.3390/f12050628.
Full textAbstract:
The induction of defense responses in Pinus sylvestris L. seedlings by methyl jasmonate (MeJA) was investigated in three experiments. Two different MeJA application methods were tested, and induction of defense responses was assayed by seedling inoculation with Heterobasidion annosum (Fr.) Bref. and Lophodermium seditiosum Minter, Staley and Millar. In the first experiment, five-year-old P. sylvestris ramets of one clone were directly treated with MeJA, followed by inoculation with H. annosum. In the second experiment, open-pollinated Scots pine seedlings were treated with MeJA by direct spraying and vaporization, and inoculation with H. annosum was done using a slightly modified protocol. In the third experiment, open-pollinated Scots pine seedlings were treated with MeJA by vaporization and inoculated with L. seditiosum. Direct application of MeJA induced seedling mortality, and in some cases, decreased resistance to inoculation with H. annosum. Application of MeJA by vaporization was less stressful for seedlings, and resulted in increased resistance to both H. annosum and L. seditiosum. In addition, an unforeseen Neodiprion sertifer (Geoffroy) and Hylobius abietis L. infestation provided anecdotal evidence of the efficacy of MeJA in inducing resistance to insect pests as well. Further studies are required on the induction of resistance to additional diseases and pests. Induced resistance could be used as a possible protective mechanism for Scots pine seedlings prior to planting during reforestation of stands to increase vitality and survival.
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Parent, Sylvain, and Jean-Claude Ruel. "Chronologie de la croissance chez des semis de sapin baumier (Abies balsamea (L.) Mill.) après une coupe à blanc avec protection de la régénération." Forestry Chronicle 78, no. 6 (2002): 876–85. http://dx.doi.org/10.5558/tfc78876-6.
Full textAbstract:
The method of harvesting with protection of the advanced regeneration consists of a complete removal of the main canopy to release a seedling bank established under the overstory shade. After harvesting, seedlings acclimated to understory conditions could suffer from moisture stress, especially the small, juvenile seedlings (less than six years). The objective of the study is to determine the capacity of understory-acclimated balsam fir seedlings to respond positively and immediately to release. The response to release was studied in two seedling populations belonging to two distinct climatic regions of Quebec, the Western and the Eastern sections of the balsam fir-white birch ecological domain. Results show that the response patterns were similar in both populations. Response to release occurred in two steps. One year after harvesting, basal ring width was on the average five times larger than prior to harvesting (p > 0.001). Height growth only became significantly higher the second year after release (p < 0.001). On average, juveniles showed higher height growth rates (height growth/height) than older seedlings. This rate was negatively correlated to seedling height at harvesting (r = -0,68, p < 0.001). Our study clearly shows that balsam fir seedlings can respond immediately and positively to large openings. The strong response of juvenile seedlings to release indicates that these can contribute significantly to the future stand. The geographic and climatic differences between the two stands under study suggest that these observations apply to a wide range of balsam fir stands. Key words: advance growth, balsam fir, release
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Oberthür, Thomas, Marianne Samson, Noel Janetski, Kate Janetski, and Myles Fisher. "Response of Cacao Seedlings to Fertilizer." Better Crops with Plant Food 102, no. 4 (2018): 20–23. http://dx.doi.org/10.24047/bc102420.
Full textAbstract:
Researchers combined a suite of good agricultural practices with fertilizer application. Modest amounts of fertilizer applied to cacao seedlings in the nursery increased seedling growth and nutrient concentrations. There were no significant responses if fertilizer application rates were doubled. Results find it likely that adequate and well-timed supplies of fertilizer nutrients in the nursery will translate into better long-term agronomic performance in farmers’ fields.