[Objective]The study was conducted to investigate the effects of shading treatments on growth of Asimina triloba （L） Dunal seedlings and provided the theoretical basis for seedling production. [Method]70 day-old A. ...[Objective]The study was conducted to investigate the effects of shading treatments on growth of Asimina triloba （L） Dunal seedlings and provided the theoretical basis for seedling production. [Method]70 day-old A. triloba seedlings had similar stem diameter and plant height and good growth vigour were taken as tested materials in 2005. 4 light gradient treatments which were the natural light with 100% light intensity, one-layer, two-layer and three-layer black shading network with the light transmittance rate of 50%, 25% and 12.5% were set up to study the effects of different shading treatments on growth of A. triloba. [ Result] With the shading treatments of one-layer and two-layer net, the plants of A. triloba seedlings grew rapidly. As the intensity of illumination decreased, the cetents of chlorophyll a （ Chl. a）, chlorophyll b （ Chl. b） and total chlorophyll increased at first and then reduced. At the same time the chlorophyll a/b value became smaller. Under natural light, the plants tended to consume more water and the soil temperature at 15：00 p. m was higher. There was a smaller difference among various treatments. [ Conclusion]The suitable shading treatment to the growth of A. triloba seedlings was under the light transmittance rate of 50% and height and stem diameter of trees increased fast. Chlorophyll a （ Chl. a）, chlorophyll b （ Chl. b） content in leaves of A. triloba seedlings were highest comparing with those in other conditions.展开更多
[ Objective] The study aimed to reveal the effects of hypergravity on salt tolerance of wheat seedlings. [ Method ] The seed germination rate （Gr） and germination index （Gi） of wheat seedlings were measured under ...[ Objective] The study aimed to reveal the effects of hypergravity on salt tolerance of wheat seedlings. [ Method ] The seed germination rate （Gr） and germination index （Gi） of wheat seedlings were measured under hypergravity of 600 × g or 1 000 × g for 4 h and under the stress of 0.4% or 0.9% salt solution. The catalase （CAT） activity and malondialdehyde （MDA） content of wheat seedlings were also measured under 0.4% salt stress. [Result] Compared with seedlings in CK group （no hypergravity or salt stress）, the Gr and Gi of the seedlings in salt stress treatment decreased to different extents; while the Gr and Gi of the seedlings in treatment group （hypergravity and salt stress） increased compared with that in salt stress group. CAT in seedlings of hypergravity treatment was higher than that of CK group and 0.4% salt treatment group, meanwhile the MDA showed an opposite result. [ Conclusion] Hypergravity could enhance the salt resistance of wheat in specific range, and hypergravity of 600 × g for 4 h performed better than that of 1 000 ×g for 4 h.展开更多
Fifty cultivated Catharanthus roseus seedlings were selected for tip-pruning treatment and the effects of tip-pruning on seedling growth and source-sink regulation were investigated for revealing physiological mechani...Fifty cultivated Catharanthus roseus seedlings were selected for tip-pruning treatment and the effects of tip-pruning on seedling growth and source-sink regulation were investigated for revealing physiological mechanisms of plants. The results showed that tip-pruning treatment resulted in obvious inhibition of apical dominance and enhancement of branching numbers. The contents of soluble sugars, acid sucrose invertase activity (AI) had a great change in differently positional leaves of the seedling. The sink strength in tip leaves of seedlings dramatically declined after tip-pruning treatment, while that in the leaves at the middle and bottom of seedlings had no obvious changes. The inhibition of apical dominance of tip leaves of seedlings was caused by the diminished sink strength due to tip-pruning treatment,展开更多
The paper aimed to investigate the growth of seedlings of three species of Cassia （C tora, C. sophera and C occidentalis） at different concentrations of salinity （NaC1） and pH treatments. All the species showed th...The paper aimed to investigate the growth of seedlings of three species of Cassia （C tora, C. sophera and C occidentalis） at different concentrations of salinity （NaC1） and pH treatments. All the species showed the highest seedling length under control condition, and with the increase of salinity, C occidentalis showed the highest sensitivity. The seedling length of C tora at 0.05 M NaCI significantly （P = 0.05） decreased to 5.71 cm, and further increase of salinity to 0.1 M, the seedling length was decreased to less than the value of 0.05 M NaC1 treatment and one-third （2.15 cm） of that of control （6.92 cm）. Seeds of all the species failed to germinate at 0.5 M NaC1. Scarified seeds of C. sophera and C occidentalis increased seedling length. The highest seedling length was in C. sophera, followed by C. tora and C. occidentalis. All the species showed significant decrease （P 〈 0.05） of fresh weight with the increase of salinity; scarification of seeds in C. occidentalis and C. sophera showed higher fresh weight than those of without scarification. Experiments at different pH levels did not show any significant （P = 0.05） change in seedling length, except C. sophera, while at acidic pH, both seedling length and dry weight were significantly （P 〈 0.05） decreased.展开更多
[Objective]we checked the role of various proportion of three growth promoting bacteria to determine the optimum proportion with greater symbiosis in cucumber seedlings. [Method]Three strains of Rhodopseudomonas palus...[Objective]we checked the role of various proportion of three growth promoting bacteria to determine the optimum proportion with greater symbiosis in cucumber seedlings. [Method]Three strains of Rhodopseudomonas palustrisSH2,Bacillus megateriumSHⅡ3,Bacillus mucilaginosusSH1 were applied in this study. Cucumber were cultured in plastic pot,inoculating mixture with seven different proportion for 28 days. [Result]2:1:2 treatment had the strongest effect on N,P,K uptake and concentrations in the soils,on increasing enrich of Fe and Zn inroots and shoots and on plant height,stem diameter,dry weight,relative chlorophyll contents. Treatments of 1:1:2 and 1:1:1 were following ,while the weakest effect was given by 1:2:2,2:2:1 and 1:2:1 treatments. [Conclusion]2:1:2 is the optimum proportion of the three bacteria for nutrition uptake and growth of cucumber seedlings.展开更多
Byrsonima intermedia A. Juss. is a species from the Brazilian Cerrado that produces edible fruits and, in common with other species from the Byrsonima genus, has pharmacological potential. Previous attempts to propaga...Byrsonima intermedia A. Juss. is a species from the Brazilian Cerrado that produces edible fruits and, in common with other species from the Byrsonima genus, has pharmacological potential. Previous attempts to propagate the species through conventional methods showed difficulties. Thus, the purpose of this work was to characterize pro-embryogenic masses of Byrsonima intermedia callus, aiming for their in vitro propagation through somatic embryogenesis. Leaf segments from in vitro germinated seedlings were employed as explants for callus production. The calli were then subcultured and exposed to dyes to fulfill their embryogenic potential. Digitalizations of the cytological preparations were made in order to measure the area that was stained by both Aceto-Carmine and Evans-Blue, using image tool software. Somatic embryos were induced after treatments with l-naphthaleneacetic acid （NAA）. The percentages of double-colored areas （by Aceto-Carmine and Evans-Blue） were calculated and the data were analyzed by using the Skott-Knott test （P ≤ 0.05） and, the embryogenic callus, as well as the formation of somatic embryos were analyzed by using the Krsuskal-Wallis rank test （P ≤0.05）. The results show that double coloration is effective at identifying cells showing embryogenic potential. Early callus subculture phases show a larger percentage ofembryogenic area （83%） Somatic embryos were induced by using high auxin level.展开更多
Studies were conducted to detennine the effects of hot water （50 ℃） and fungicide （contizeb ‘5＇） treatments on avocado seeds in terms of seed health, germination and seedling growth before side-grafting. The le...Studies were conducted to detennine the effects of hot water （50 ℃） and fungicide （contizeb ‘5＇） treatments on avocado seeds in terms of seed health, germination and seedling growth before side-grafting. The leathery coverings or seed coat were removed and either 1 cm or 1.5 cm of the narrow top of the seeds was removed before sowing. There were six treatments arranged in a randomized complete block and rephcated three times. In a six week period after germination when side grafting could be done, it was found out that the earliest germination came from the ＇no hot water or fungicide-treated＂ seeds cut at 1 cm but most seeds germinated from the fungicide-treated seeds at 1 cm cut. Most fungi including Fusarium andAspergillus spp found to either delay germination or reduce seedling vigour were minimized in number through the fungicide treatment compared to the hot water-treated seeds. Seedlings performance in terms of shoot extension and canopy development was significantly better in the fungicide-treated seeds than from either the hot water or the non-treated seeds. The study concluded that avocado seed treatment prior to sowing enhanced germination.展开更多
基金Supported by the National"948"Import Program(2001-46)~~
文摘[Objective]The study was conducted to investigate the effects of shading treatments on growth of Asimina triloba （L） Dunal seedlings and provided the theoretical basis for seedling production. [Method]70 day-old A. triloba seedlings had similar stem diameter and plant height and good growth vigour were taken as tested materials in 2005. 4 light gradient treatments which were the natural light with 100% light intensity, one-layer, two-layer and three-layer black shading network with the light transmittance rate of 50%, 25% and 12.5% were set up to study the effects of different shading treatments on growth of A. triloba. [ Result] With the shading treatments of one-layer and two-layer net, the plants of A. triloba seedlings grew rapidly. As the intensity of illumination decreased, the cetents of chlorophyll a （ Chl. a）, chlorophyll b （ Chl. b） and total chlorophyll increased at first and then reduced. At the same time the chlorophyll a/b value became smaller. Under natural light, the plants tended to consume more water and the soil temperature at 15：00 p. m was higher. There was a smaller difference among various treatments. [ Conclusion]The suitable shading treatment to the growth of A. triloba seedlings was under the light transmittance rate of 50% and height and stem diameter of trees increased fast. Chlorophyll a （ Chl. a）, chlorophyll b （ Chl. b） content in leaves of A. triloba seedlings were highest comparing with those in other conditions.
基金the Start-up Research Grant of Excellent Talent in ZhongKai University of Agriculture and Engineering (G2360250)Shanxi Natural Science Foundation (20031067)~~
文摘[ Objective] The study aimed to reveal the effects of hypergravity on salt tolerance of wheat seedlings. [ Method ] The seed germination rate （Gr） and germination index （Gi） of wheat seedlings were measured under hypergravity of 600 × g or 1 000 × g for 4 h and under the stress of 0.4% or 0.9% salt solution. The catalase （CAT） activity and malondialdehyde （MDA） content of wheat seedlings were also measured under 0.4% salt stress. [Result] Compared with seedlings in CK group （no hypergravity or salt stress）, the Gr and Gi of the seedlings in salt stress treatment decreased to different extents; while the Gr and Gi of the seedlings in treatment group （hypergravity and salt stress） increased compared with that in salt stress group. CAT in seedlings of hypergravity treatment was higher than that of CK group and 0.4% salt treatment group, meanwhile the MDA showed an opposite result. [ Conclusion] Hypergravity could enhance the salt resistance of wheat in specific range, and hypergravity of 600 × g for 4 h performed better than that of 1 000 ×g for 4 h.
基金The research was Supported by the Natural Science Foundation of Heilongjiang Province (C200511)
文摘Fifty cultivated Catharanthus roseus seedlings were selected for tip-pruning treatment and the effects of tip-pruning on seedling growth and source-sink regulation were investigated for revealing physiological mechanisms of plants. The results showed that tip-pruning treatment resulted in obvious inhibition of apical dominance and enhancement of branching numbers. The contents of soluble sugars, acid sucrose invertase activity (AI) had a great change in differently positional leaves of the seedling. The sink strength in tip leaves of seedlings dramatically declined after tip-pruning treatment, while that in the leaves at the middle and bottom of seedlings had no obvious changes. The inhibition of apical dominance of tip leaves of seedlings was caused by the diminished sink strength due to tip-pruning treatment,
文摘The paper aimed to investigate the growth of seedlings of three species of Cassia （C tora, C. sophera and C occidentalis） at different concentrations of salinity （NaC1） and pH treatments. All the species showed the highest seedling length under control condition, and with the increase of salinity, C occidentalis showed the highest sensitivity. The seedling length of C tora at 0.05 M NaCI significantly （P = 0.05） decreased to 5.71 cm, and further increase of salinity to 0.1 M, the seedling length was decreased to less than the value of 0.05 M NaC1 treatment and one-third （2.15 cm） of that of control （6.92 cm）. Seeds of all the species failed to germinate at 0.5 M NaC1. Scarified seeds of C. sophera and C occidentalis increased seedling length. The highest seedling length was in C. sophera, followed by C. tora and C. occidentalis. All the species showed significant decrease （P 〈 0.05） of fresh weight with the increase of salinity; scarification of seeds in C. occidentalis and C. sophera showed higher fresh weight than those of without scarification. Experiments at different pH levels did not show any significant （P = 0.05） change in seedling length, except C. sophera, while at acidic pH, both seedling length and dry weight were significantly （P 〈 0.05） decreased.
文摘[Objective]we checked the role of various proportion of three growth promoting bacteria to determine the optimum proportion with greater symbiosis in cucumber seedlings. [Method]Three strains of Rhodopseudomonas palustrisSH2,Bacillus megateriumSHⅡ3,Bacillus mucilaginosusSH1 were applied in this study. Cucumber were cultured in plastic pot,inoculating mixture with seven different proportion for 28 days. [Result]2:1:2 treatment had the strongest effect on N,P,K uptake and concentrations in the soils,on increasing enrich of Fe and Zn inroots and shoots and on plant height,stem diameter,dry weight,relative chlorophyll contents. Treatments of 1:1:2 and 1:1:1 were following ,while the weakest effect was given by 1:2:2,2:2:1 and 1:2:1 treatments. [Conclusion]2:1:2 is the optimum proportion of the three bacteria for nutrition uptake and growth of cucumber seedlings.
文摘Byrsonima intermedia A. Juss. is a species from the Brazilian Cerrado that produces edible fruits and, in common with other species from the Byrsonima genus, has pharmacological potential. Previous attempts to propagate the species through conventional methods showed difficulties. Thus, the purpose of this work was to characterize pro-embryogenic masses of Byrsonima intermedia callus, aiming for their in vitro propagation through somatic embryogenesis. Leaf segments from in vitro germinated seedlings were employed as explants for callus production. The calli were then subcultured and exposed to dyes to fulfill their embryogenic potential. Digitalizations of the cytological preparations were made in order to measure the area that was stained by both Aceto-Carmine and Evans-Blue, using image tool software. Somatic embryos were induced after treatments with l-naphthaleneacetic acid （NAA）. The percentages of double-colored areas （by Aceto-Carmine and Evans-Blue） were calculated and the data were analyzed by using the Skott-Knott test （P ≤ 0.05） and, the embryogenic callus, as well as the formation of somatic embryos were analyzed by using the Krsuskal-Wallis rank test （P ≤0.05）. The results show that double coloration is effective at identifying cells showing embryogenic potential. Early callus subculture phases show a larger percentage ofembryogenic area （83%） Somatic embryos were induced by using high auxin level.
文摘Studies were conducted to detennine the effects of hot water （50 ℃） and fungicide （contizeb ‘5＇） treatments on avocado seeds in terms of seed health, germination and seedling growth before side-grafting. The leathery coverings or seed coat were removed and either 1 cm or 1.5 cm of the narrow top of the seeds was removed before sowing. There were six treatments arranged in a randomized complete block and rephcated three times. In a six week period after germination when side grafting could be done, it was found out that the earliest germination came from the ＇no hot water or fungicide-treated＂ seeds cut at 1 cm but most seeds germinated from the fungicide-treated seeds at 1 cm cut. Most fungi including Fusarium andAspergillus spp found to either delay germination or reduce seedling vigour were minimized in number through the fungicide treatment compared to the hot water-treated seeds. Seedlings performance in terms of shoot extension and canopy development was significantly better in the fungicide-treated seeds than from either the hot water or the non-treated seeds. The study concluded that avocado seed treatment prior to sowing enhanced germination.
