Background Light is a critical factor in plant growth and development,particularly in controlled environments.Light-emitting diodes(LEDs)have become a reliable alternative to conventional high pressure sodium(HSP)lamp...Background Light is a critical factor in plant growth and development,particularly in controlled environments.Light-emitting diodes(LEDs)have become a reliable alternative to conventional high pressure sodium(HSP)lamps because they are more efficient and versatile in light sources.In contrast to well-known specialized LED light spectra for vegetables,the appropriate LED lights for crops such as cotton remain unknown.Results In this growth chamber study,we selected and compared four LED lights with varying percentages(26.44%–68.68%)of red light(R,600–700 nm),combined with other lights,for their effects on growth,leaf anatomy,and photosynthesis of cotton seedlings,using HSP lamp as a control.The total photosynthetic photon flux density(PPFD)was(215±2)μmol·m-2·s-1 for all LEDs and HSP lamp.The results showed significant differences in all tested parameters among lights,and the percentage of far red(FR,701–780 nm)within the range of 3.03%–11.86%was positively correlated with plant growth(characterized by leaf number and area,plant height,stem diameter,and total biomass),palisade layer thickness,photosynthesis rate(Pn),and stomatal conductance(Gs).The ratio of R/FR(4.445–11.497)negatively influenced the growth of cotton seedlings,and blue light(B)suppressed stem elongation but increased palisade cell length,chlorophyll content,and Pn.Conclusion The LED 2 was superior to other LED lights and HSP lamp.It had the highest ratio of FR within the total PPFD(11.86%)and the lowest ratio of R/FR(4.445).LED 2 may therefore be used to replace HPS lamp under controlled environments for the study of cotton at the seedling stage.展开更多
To investigate the effects of silicon formulations on the cold tolerance of rice seedlings,Song Japonica 16(not cold tolerant)and Dongnong 427(cold tolerant)rice varieties were used as test materials and four differen...To investigate the effects of silicon formulations on the cold tolerance of rice seedlings,Song Japonica 16(not cold tolerant)and Dongnong 427(cold tolerant)rice varieties were used as test materials and four different types of silicon formulations,Si-50-G,Si-60-G,Si-T-G,and Si-E-G,were applied as foliar sprays at the seedling stage,and a control group CK(equal amount of distilled water)was set up.One week after the first silicon spray,two types of rice were subjected to low-temperature stress treatments at day/night temperatures of 12℃/10℃for 2,4,6,and 8 days.The effects of different silicon formulations on the chlorophyll,proline(Pro)and soluble sugar contents as well as superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)activities of rice seedlings under low-temperature stress were compared to find out the effects of silicon formulations on the cold tolerance of rice seedlings.The results showed that silicon formulations could significantly increase the chlorophyll content of rice seedling leaves,with Si-50-G being the most effective,with a significant increment of 40.17%compared to the CK at 2 days of low temperature.Four silicon formulations significantly increased the proline content and soluble sugar content of rice leaves at low temperature for 4-8 days.For Song Japonica 16,the most significant increment in leaf POD activity was observed in Si-E-G treatment at 2,4 and 8 days of temperature stress,with 73.58%,20.95%and 217.24%increases compared to the CK,respectively.For 4 and 6 days of temperature stress,the most significant increase in CAT activity was observed in Si-E-G treatment,with 25.70%and 75.78%increases compared to the CK,respectively.For Dongnong 427,the Si-60-G treatment showed the highest increase in leaf SOD activity for 4 and 8 days of temperature stress,with significant increases of 58.15%and 82.76%compared to the CK,respectively,and the Si-E-G treatment showed the highest increase in leaf POD activity for 2 and 8 days of temperature stress,with significant increases of 97.75%and 245.10%compared to the CK,respectively.It showed that the spraying of silicon formulations could significantly enhance the cold tolerance of rice.This study provided a scientific basis for the rational use of silicon formulations to enhance cold tolerance in rice and had important theoretical and practical significance for ensuring sustainable high and stable rice yields in Heilongjiang Province,as well as for the development of silicon fertilizers.展开更多
The process of rice(Oryza sativa L.)seedling cultivation is often subjected to adverse environmental stress.Biostimulants regulate the robust growth of rice seedlings and play a crucial role in promoting the green and...The process of rice(Oryza sativa L.)seedling cultivation is often subjected to adverse environmental stress.Biostimulants regulate the robust growth of rice seedlings and play a crucial role in promoting the green and ecological development of agriculture.In this study,1.0 and 2.0 g•m^(-2) of the biostimulant were applied to soil in rice seedbeds.Growth indicators of rice,antioxidant enzyme activities and soil physicochemical characteristics were assessed at the 2.5-leaf and 4-leaf stages of rice.The results indicated that applying 2.0 g•m^(-2) of the biostimulant at both the 2.5-leaf and 4-leaf stages had the most significant promoting effect on rice growth.At the 2.5-leaf and 4-leaf stages,the number of fibrous roots increased by 23.43%and 22.25%,stem base width increased by 19.05%and 19.58%,above ground dry weight increased by 18.09%and 16.47%,root dry weight increased by 19.67%and 18.28%,leaf peroxidase(POD)activity increased by 34.44%and 42.94%,superoxide dismutase(SOD)activity increased by 37.24%and 56.79%,malondialdehyde(MDA)content decreased by 18.60%and 27.67%,and chlorophyll content increased significantly by 28.31%and 34.24%,respectively.At the 4-leaf stage of rice,urease,phosphatase and cellulase activities in the seedbed soil increased by 42.13%,25.96%and 33.59%,respectively,while soil alkaline nitrogen,available phosphorus and available potassium content decreased by 19.76%,19.02%and 17.88%,respectively.The application of biostimulants played a crucial role in promoting the growth of rice seedlings and enhancing soil nutrient absorption.展开更多
DCPTA （2-diethylaminoethyl-3, 4-dichlorophenylether） is a new plant regulator which can be used to regulate growth and development for crops. Experiments on maize seedlings were conducted in the growth chamber to st...DCPTA （2-diethylaminoethyl-3, 4-dichlorophenylether） is a new plant regulator which can be used to regulate growth and development for crops. Experiments on maize seedlings were conducted in the growth chamber to study the effects of foliar applied DCPTA. The plant pots were placed in a completely randomized design with three replicates. The maize seedlings were treated with 0 mg·L-1 （control）, 20 mg·L-1 and 40 mg·L-1 DCPTA solution. The effects of DCPTA on the photosynthetic characteristics （photosynthesis, stomata conductance, intercellular CO2, and transpiration rate）, related physiological characteristics （contents of soluble sugar and starch）, chlorophyll fluorescence parameters （Fo, Fro, Fv/Fm, Fv/Fo, qP, and qN） and the weight of dry matter in maize seedling were studied. The results showed that DCPTA enhanced photosynthesis of maize seedling. In general, photosynthetic rate in leaves was significantly promoted through spraying DCPTA solution, and 40 rag＂ L~ DCPTA was found to be the best concentration for maize. The relationship between stomata conductance and transpiration rate in maize leaves could be described as linear. With regard to the chlorophyll fluorescence parameters, our fmdings showed that 40 mg·L-1 DCPTA in maize seedling caused an increase in Fm, Fv/Fm, Fm/Fo, qP and a decrease in Fo and qN at some time points checked. It is suggested that DCPTA increased photosynthetic rate by raising both the content of chlorophyll and activities of PSII and the contents of sugar and starch. Compared with the control, the treated maize seedling caused an increase in plant height, root length, shoot dry mass, root dry mass, or the total （root plus shoot） dry mass.展开更多
Three varieties were employed as materials to study changes of photosynthetic traits under low-temperature stress. The results showed that Pn, Gs and Tr decreased under low-temperature treatment. Ci decreased under lo...Three varieties were employed as materials to study changes of photosynthetic traits under low-temperature stress. The results showed that Pn, Gs and Tr decreased under low-temperature treatment. Ci decreased under low-temperature treatment 18℃/ 9℃, and 16℃/7℃, and it decreased in earlier stage after increased under 14℃/5℃. WUE was increased in earlier stage and after stabilized. The order of the three varieties of cold resistance were Jinyu 5〉Xingken 3〉Jidan 198. They could make self-regulation through adjusting Gs, Tr, Ci and WUE.展开更多
In the present paper, an experiment was conducted to study the effects of soil moisture content on dry nursery seedling quality in Guangzhou in 1995. Through comparing the difference of dry nursery seedlings and wet n...In the present paper, an experiment was conducted to study the effects of soil moisture content on dry nursery seedling quality in Guangzhou in 1995. Through comparing the difference of dry nursery seedlings and wet nursery seedlings, we found a close relationship between soil moisture content and seedling growth. The seedling emergence of dry nursery seedling was more even, tidy and faster, and the survival rate was higher than that of wet nursery seedling. Dry nursery seedlings had small plant stature, slow leaf stretching speed and low individual seedling dry weight, but had high dry/fresh weight ratio. This was abeneficial factor for seedlings to recover from transplanting shock more quickly. As com-pared with the wet nursery seedlings, dry nursery seedlings had poor rooting ability,but had more vigorous white roots and fewer rust roots. It was the possibly important reasonfor dry nursery seedlings to form strong“explosive force”.展开更多
The inhibitory effect of lead on the seed germination and seedling growth was obvi-ously seen in barley,sorghum and wheat.Their differential reactions on the lead solution werefound under the lead stress during the se...The inhibitory effect of lead on the seed germination and seedling growth was obvi-ously seen in barley,sorghum and wheat.Their differential reactions on the lead solution werefound under the lead stress during the seed germination and seedling growth stages.Wheat ismore sensitive to lead than the other three plants.This can be used to select new crops which canresist lead damage.The changes of the peroxidase and polyphenol oxidase isozymes have beenfound in individual plants which was injured by a lead solution at the seedling and root develop-ment stages.The authors suggest that these isozymes,which have been changed in patterns andnumbers,may be adaptive isozymes.Adaptive isozymes are produced in plant tissue when plantsare in harmful environmental conditions.The change in environmental conditions influences theexpression of the gene which encode peroxidase,polyphenol oxidase isozymes,and promote forma-tion of the adaptive isozymes.展开更多
During the period of dry nursery seedling raising of late double cropping indica rice in South China, both chemical fertilizer and farmyard manure did not show obvious effect on the growth of shoot and root in young s...During the period of dry nursery seedling raising of late double cropping indica rice in South China, both chemical fertilizer and farmyard manure did not show obvious effect on the growth of shoot and root in young seedlings at 4-leaf stage （18-day-old seedling）, but had significant effects on root growth in old seedlings with 6-7 leaves （27-day-old seedling） at suitable seeding densities (65-125g m<sup>-2</sup>). There were satistically significant differences （at 0.01 or 0.05 levels）between treatments in root number and rooting ability of root-pruned seedlings.展开更多
In order to investigate the physiological injury of barley caused by the low temperature after herbicides, tillering barley seedlings planted in plastic cups were pretreated in illumination incubator at 15℃ and 12 h-...In order to investigate the physiological injury of barley caused by the low temperature after herbicides, tillering barley seedlings planted in plastic cups were pretreated in illumination incubator at 15℃ and 12 h-light per day for 7 days, and then subjected to herbicide treatment, prometryn （with the concentrations of 0, 0.15%, 0.30%, and 0.45%） or isoproturon （with the concentrations of 0, 0.30%, 0.60%, and 0.90%）, and the SOD activity, the CAT activity, the POD activity, the MDA content, proline content, soluble protein content, electrical conductivity, and the rate of O2 were determined and analyzed. The results showed that the low-temperature was the most important, and the treatment-time of low-temperature was another significant influencing factor on the physiological and biochemical indices of barley seedlings. However, all of the physiological and biochemical indices determined were not affected by the kinds of herbicides and herbicide concentrations, and the SOD was stable and should play the more prominent role on extracting of free radicals according to the stepwise regression and correlation. The herbicide concentrations should be increased in the future research for truly reflecting the effects of the herbicide concentration on the physiological and biochemical indices of barley seedlings.展开更多
The effects of 6-benzylaminopurine （6-BA） on several physiological indexes of Caryota mitis and C. obtusa seedlings treated at varied temperatures were conducted, the leaves of the two palm species were sprayed with...The effects of 6-benzylaminopurine （6-BA） on several physiological indexes of Caryota mitis and C. obtusa seedlings treated at varied temperatures were conducted, the leaves of the two palm species were sprayed with 0, 25, 50 and 100 mg · L1 6-BA solutions, the activities of superoxide dismutase （SOD）, peroxidase （POD）, and the contents of malondialdehyde （MDA）, proline, soluble protein, chlorophyll and chlorophyll a/b were determined under 25 ℃, 5 ℃ and 25 ℃ for 24 h, respectively. The dynamics of a series of important physiological components derived from the leaves were studied. It was indicated that all the above mentioned physiological indexes varied with different concentrations of 6-BA and temperature. The fuzzy comprehensive evaluation values for different concentrations of 6-BA at the recovery temperature 25℃ were 0.33, 0.28, 0.92 and 0.33, respectively for C. mitis, and 0.20, 0.49, 0.56 and 0.63, respectively for C. obtusa. It was concluded that leaves sprayed with different concentrations of 6-BA could affect the cold tolerance of palm seedlings. The optimal concentration of 6-BA was different for different palm species.展开更多
Forestation in the increasingly urbanized area generates a huge demand for ornamental tree stocks, requiring new approach to promote the cultural efficiency of highly valued seedlings. Chitosan oligosaccharide(COS) is...Forestation in the increasingly urbanized area generates a huge demand for ornamental tree stocks, requiring new approach to promote the cultural efficiency of highly valued seedlings. Chitosan oligosaccharide(COS) is one of biodegradable natural plant growth modifier derived from chitin and an abundant water insoluble biopolymer. In this study, Buddhist pine(Podocarpus macrophyllus)(PM) and Northeast yew(Taxus cuspidata)(TC) were cultured with or without COS addition from 1 July to 17 November 2016. Relative to the TC seedlings, the PM seedlings had greater growth of height and biomass which was found to be negatively correlated with the changes of nitrogen(N) and phosphorus(P) concentrations in shoot during the culture. Only those TC seedlings treated without COS addition had higher proportion of decline in the initial N concentration than that in the PM seedlings. Root P concentration declined less in Buddhist pine seedlings than that in Northeast yew seedlings treated with COS. By 17 of November 2016, both N and P seemed to have been diluted in the PM seedlings and exceed the demand in the TC seedlings. In conclusion, COS had the potential to be used for the culture of ornamental tree seedlings to promote nutrient utilization for shoot biomass accumulation, but more specific effect on nutrient allocation and utilization need to be confirmed by more studies.展开更多
To improve the efficiency of fetching and transplanting seedlings for the mechanization of strawberry planting,an integrated transplanting mechanism was designed with protruding,fetching and planting performance to ac...To improve the efficiency of fetching and transplanting seedlings for the mechanization of strawberry planting,an integrated transplanting mechanism was designed with protruding,fetching and planting performance to achieve rapid fetching and pushing bowl movements.According to the working principle of the slewing mechanism,a kinematics model and the optimization goal were established,respectively.Based on visual auxiliary analysis software,optimal parameters were obtained.A three-dimensional model was established to obtain a simulation trajectory by means of a virtual simulation design analysis.Three-dimensional printing technology was used to manufacture the test prototype,and the actual working trajectories of the test prototype were extracted using high-speed photography technology,which verified the consistency of the actual trajectory with the theoretical and simulated trajectories.A prototype transplanting experiment was performed with the success rate of seedling extraction of 91.2%and excellent planting rate of 82.8%,which met the requirements for integrated strawberry harvesting,planting and transplanting.The experimental results verified the correctness and feasibility of the design of integrated transplanting mechanism.展开更多
基金funded by the China Agriculture Research System(CARS-15-16).
文摘Background Light is a critical factor in plant growth and development,particularly in controlled environments.Light-emitting diodes(LEDs)have become a reliable alternative to conventional high pressure sodium(HSP)lamps because they are more efficient and versatile in light sources.In contrast to well-known specialized LED light spectra for vegetables,the appropriate LED lights for crops such as cotton remain unknown.Results In this growth chamber study,we selected and compared four LED lights with varying percentages(26.44%–68.68%)of red light(R,600–700 nm),combined with other lights,for their effects on growth,leaf anatomy,and photosynthesis of cotton seedlings,using HSP lamp as a control.The total photosynthetic photon flux density(PPFD)was(215±2)μmol·m-2·s-1 for all LEDs and HSP lamp.The results showed significant differences in all tested parameters among lights,and the percentage of far red(FR,701–780 nm)within the range of 3.03%–11.86%was positively correlated with plant growth(characterized by leaf number and area,plant height,stem diameter,and total biomass),palisade layer thickness,photosynthesis rate(Pn),and stomatal conductance(Gs).The ratio of R/FR(4.445–11.497)negatively influenced the growth of cotton seedlings,and blue light(B)suppressed stem elongation but increased palisade cell length,chlorophyll content,and Pn.Conclusion The LED 2 was superior to other LED lights and HSP lamp.It had the highest ratio of FR within the total PPFD(11.86%)and the lowest ratio of R/FR(4.445).LED 2 may therefore be used to replace HPS lamp under controlled environments for the study of cotton at the seedling stage.
基金the National Natural Science Foundation of China(31471440)。
文摘To investigate the effects of silicon formulations on the cold tolerance of rice seedlings,Song Japonica 16(not cold tolerant)and Dongnong 427(cold tolerant)rice varieties were used as test materials and four different types of silicon formulations,Si-50-G,Si-60-G,Si-T-G,and Si-E-G,were applied as foliar sprays at the seedling stage,and a control group CK(equal amount of distilled water)was set up.One week after the first silicon spray,two types of rice were subjected to low-temperature stress treatments at day/night temperatures of 12℃/10℃for 2,4,6,and 8 days.The effects of different silicon formulations on the chlorophyll,proline(Pro)and soluble sugar contents as well as superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)activities of rice seedlings under low-temperature stress were compared to find out the effects of silicon formulations on the cold tolerance of rice seedlings.The results showed that silicon formulations could significantly increase the chlorophyll content of rice seedling leaves,with Si-50-G being the most effective,with a significant increment of 40.17%compared to the CK at 2 days of low temperature.Four silicon formulations significantly increased the proline content and soluble sugar content of rice leaves at low temperature for 4-8 days.For Song Japonica 16,the most significant increment in leaf POD activity was observed in Si-E-G treatment at 2,4 and 8 days of temperature stress,with 73.58%,20.95%and 217.24%increases compared to the CK,respectively.For 4 and 6 days of temperature stress,the most significant increase in CAT activity was observed in Si-E-G treatment,with 25.70%and 75.78%increases compared to the CK,respectively.For Dongnong 427,the Si-60-G treatment showed the highest increase in leaf SOD activity for 4 and 8 days of temperature stress,with significant increases of 58.15%and 82.76%compared to the CK,respectively,and the Si-E-G treatment showed the highest increase in leaf POD activity for 2 and 8 days of temperature stress,with significant increases of 97.75%and 245.10%compared to the CK,respectively.It showed that the spraying of silicon formulations could significantly enhance the cold tolerance of rice.This study provided a scientific basis for the rational use of silicon formulations to enhance cold tolerance in rice and had important theoretical and practical significance for ensuring sustainable high and stable rice yields in Heilongjiang Province,as well as for the development of silicon fertilizers.
文摘The process of rice(Oryza sativa L.)seedling cultivation is often subjected to adverse environmental stress.Biostimulants regulate the robust growth of rice seedlings and play a crucial role in promoting the green and ecological development of agriculture.In this study,1.0 and 2.0 g•m^(-2) of the biostimulant were applied to soil in rice seedbeds.Growth indicators of rice,antioxidant enzyme activities and soil physicochemical characteristics were assessed at the 2.5-leaf and 4-leaf stages of rice.The results indicated that applying 2.0 g•m^(-2) of the biostimulant at both the 2.5-leaf and 4-leaf stages had the most significant promoting effect on rice growth.At the 2.5-leaf and 4-leaf stages,the number of fibrous roots increased by 23.43%and 22.25%,stem base width increased by 19.05%and 19.58%,above ground dry weight increased by 18.09%and 16.47%,root dry weight increased by 19.67%and 18.28%,leaf peroxidase(POD)activity increased by 34.44%and 42.94%,superoxide dismutase(SOD)activity increased by 37.24%and 56.79%,malondialdehyde(MDA)content decreased by 18.60%and 27.67%,and chlorophyll content increased significantly by 28.31%and 34.24%,respectively.At the 4-leaf stage of rice,urease,phosphatase and cellulase activities in the seedbed soil increased by 42.13%,25.96%and 33.59%,respectively,while soil alkaline nitrogen,available phosphorus and available potassium content decreased by 19.76%,19.02%and 17.88%,respectively.The application of biostimulants played a crucial role in promoting the growth of rice seedlings and enhancing soil nutrient absorption.
基金Supported by the National Natural Science Foundation of China(31201164)the Program of Science and Technology of Education Department of Heilongjiang Province(12521036)+2 种基金China Postdoctoral Science Foundation(2012M511434)Heilongjiang Province Postdoctoral Science Foundation(LBH-Z12036)the Doctoral Starting Up Foundation of Northeast Agricultural University(2012RCB01)
文摘DCPTA （2-diethylaminoethyl-3, 4-dichlorophenylether） is a new plant regulator which can be used to regulate growth and development for crops. Experiments on maize seedlings were conducted in the growth chamber to study the effects of foliar applied DCPTA. The plant pots were placed in a completely randomized design with three replicates. The maize seedlings were treated with 0 mg·L-1 （control）, 20 mg·L-1 and 40 mg·L-1 DCPTA solution. The effects of DCPTA on the photosynthetic characteristics （photosynthesis, stomata conductance, intercellular CO2, and transpiration rate）, related physiological characteristics （contents of soluble sugar and starch）, chlorophyll fluorescence parameters （Fo, Fro, Fv/Fm, Fv/Fo, qP, and qN） and the weight of dry matter in maize seedling were studied. The results showed that DCPTA enhanced photosynthesis of maize seedling. In general, photosynthetic rate in leaves was significantly promoted through spraying DCPTA solution, and 40 rag＂ L~ DCPTA was found to be the best concentration for maize. The relationship between stomata conductance and transpiration rate in maize leaves could be described as linear. With regard to the chlorophyll fluorescence parameters, our fmdings showed that 40 mg·L-1 DCPTA in maize seedling caused an increase in Fm, Fv/Fm, Fm/Fo, qP and a decrease in Fo and qN at some time points checked. It is suggested that DCPTA increased photosynthetic rate by raising both the content of chlorophyll and activities of PSII and the contents of sugar and starch. Compared with the control, the treated maize seedling caused an increase in plant height, root length, shoot dry mass, root dry mass, or the total （root plus shoot） dry mass.
基金Supported by the Science and Technology Foundation(2008BADB3B09-03)
文摘Three varieties were employed as materials to study changes of photosynthetic traits under low-temperature stress. The results showed that Pn, Gs and Tr decreased under low-temperature treatment. Ci decreased under low-temperature treatment 18℃/ 9℃, and 16℃/7℃, and it decreased in earlier stage after increased under 14℃/5℃. WUE was increased in earlier stage and after stabilized. The order of the three varieties of cold resistance were Jinyu 5〉Xingken 3〉Jidan 198. They could make self-regulation through adjusting Gs, Tr, Ci and WUE.
文摘In the present paper, an experiment was conducted to study the effects of soil moisture content on dry nursery seedling quality in Guangzhou in 1995. Through comparing the difference of dry nursery seedlings and wet nursery seedlings, we found a close relationship between soil moisture content and seedling growth. The seedling emergence of dry nursery seedling was more even, tidy and faster, and the survival rate was higher than that of wet nursery seedling. Dry nursery seedlings had small plant stature, slow leaf stretching speed and low individual seedling dry weight, but had high dry/fresh weight ratio. This was abeneficial factor for seedlings to recover from transplanting shock more quickly. As com-pared with the wet nursery seedlings, dry nursery seedlings had poor rooting ability,but had more vigorous white roots and fewer rust roots. It was the possibly important reasonfor dry nursery seedlings to form strong“explosive force”.
文摘The inhibitory effect of lead on the seed germination and seedling growth was obvi-ously seen in barley,sorghum and wheat.Their differential reactions on the lead solution werefound under the lead stress during the seed germination and seedling growth stages.Wheat ismore sensitive to lead than the other three plants.This can be used to select new crops which canresist lead damage.The changes of the peroxidase and polyphenol oxidase isozymes have beenfound in individual plants which was injured by a lead solution at the seedling and root develop-ment stages.The authors suggest that these isozymes,which have been changed in patterns andnumbers,may be adaptive isozymes.Adaptive isozymes are produced in plant tissue when plantsare in harmful environmental conditions.The change in environmental conditions influences theexpression of the gene which encode peroxidase,polyphenol oxidase isozymes,and promote forma-tion of the adaptive isozymes.
文摘During the period of dry nursery seedling raising of late double cropping indica rice in South China, both chemical fertilizer and farmyard manure did not show obvious effect on the growth of shoot and root in young seedlings at 4-leaf stage （18-day-old seedling）, but had significant effects on root growth in old seedlings with 6-7 leaves （27-day-old seedling） at suitable seeding densities (65-125g m<sup>-2</sup>). There were satistically significant differences （at 0.01 or 0.05 levels）between treatments in root number and rooting ability of root-pruned seedlings.
基金Supported by the National Natural Science Foundation of China (31000712)
文摘In order to investigate the physiological injury of barley caused by the low temperature after herbicides, tillering barley seedlings planted in plastic cups were pretreated in illumination incubator at 15℃ and 12 h-light per day for 7 days, and then subjected to herbicide treatment, prometryn （with the concentrations of 0, 0.15%, 0.30%, and 0.45%） or isoproturon （with the concentrations of 0, 0.30%, 0.60%, and 0.90%）, and the SOD activity, the CAT activity, the POD activity, the MDA content, proline content, soluble protein content, electrical conductivity, and the rate of O2 were determined and analyzed. The results showed that the low-temperature was the most important, and the treatment-time of low-temperature was another significant influencing factor on the physiological and biochemical indices of barley seedlings. However, all of the physiological and biochemical indices determined were not affected by the kinds of herbicides and herbicide concentrations, and the SOD was stable and should play the more prominent role on extracting of free radicals according to the stepwise regression and correlation. The herbicide concentrations should be increased in the future research for truly reflecting the effects of the herbicide concentration on the physiological and biochemical indices of barley seedlings.
基金Supported by Fund of Xiamen Municipal Science&Technology Commision(3502Z20092019)
文摘The effects of 6-benzylaminopurine （6-BA） on several physiological indexes of Caryota mitis and C. obtusa seedlings treated at varied temperatures were conducted, the leaves of the two palm species were sprayed with 0, 25, 50 and 100 mg · L1 6-BA solutions, the activities of superoxide dismutase （SOD）, peroxidase （POD）, and the contents of malondialdehyde （MDA）, proline, soluble protein, chlorophyll and chlorophyll a/b were determined under 25 ℃, 5 ℃ and 25 ℃ for 24 h, respectively. The dynamics of a series of important physiological components derived from the leaves were studied. It was indicated that all the above mentioned physiological indexes varied with different concentrations of 6-BA and temperature. The fuzzy comprehensive evaluation values for different concentrations of 6-BA at the recovery temperature 25℃ were 0.33, 0.28, 0.92 and 0.33, respectively for C. mitis, and 0.20, 0.49, 0.56 and 0.63, respectively for C. obtusa. It was concluded that leaves sprayed with different concentrations of 6-BA could affect the cold tolerance of palm seedlings. The optimal concentration of 6-BA was different for different palm species.
基金supported by the National Natural Science Foundation of China(31600496)The National Key Research and Development Program of China(2016YFC0500307)
文摘Forestation in the increasingly urbanized area generates a huge demand for ornamental tree stocks, requiring new approach to promote the cultural efficiency of highly valued seedlings. Chitosan oligosaccharide(COS) is one of biodegradable natural plant growth modifier derived from chitin and an abundant water insoluble biopolymer. In this study, Buddhist pine(Podocarpus macrophyllus)(PM) and Northeast yew(Taxus cuspidata)(TC) were cultured with or without COS addition from 1 July to 17 November 2016. Relative to the TC seedlings, the PM seedlings had greater growth of height and biomass which was found to be negatively correlated with the changes of nitrogen(N) and phosphorus(P) concentrations in shoot during the culture. Only those TC seedlings treated without COS addition had higher proportion of decline in the initial N concentration than that in the PM seedlings. Root P concentration declined less in Buddhist pine seedlings than that in Northeast yew seedlings treated with COS. By 17 of November 2016, both N and P seemed to have been diluted in the PM seedlings and exceed the demand in the TC seedlings. In conclusion, COS had the potential to be used for the culture of ornamental tree seedlings to promote nutrient utilization for shoot biomass accumulation, but more specific effect on nutrient allocation and utilization need to be confirmed by more studies.
基金Supported by the National Natural Science Foundation of China Youth Fund Project(52005221)"the 13th Five-Year"National Key Research and Development Program:High-speed Planting Technology and Equipment Research and Development(2017YFD0700800)。
文摘To improve the efficiency of fetching and transplanting seedlings for the mechanization of strawberry planting,an integrated transplanting mechanism was designed with protruding,fetching and planting performance to achieve rapid fetching and pushing bowl movements.According to the working principle of the slewing mechanism,a kinematics model and the optimization goal were established,respectively.Based on visual auxiliary analysis software,optimal parameters were obtained.A three-dimensional model was established to obtain a simulation trajectory by means of a virtual simulation design analysis.Three-dimensional printing technology was used to manufacture the test prototype,and the actual working trajectories of the test prototype were extracted using high-speed photography technology,which verified the consistency of the actual trajectory with the theoretical and simulated trajectories.A prototype transplanting experiment was performed with the success rate of seedling extraction of 91.2%and excellent planting rate of 82.8%,which met the requirements for integrated strawberry harvesting,planting and transplanting.The experimental results verified the correctness and feasibility of the design of integrated transplanting mechanism.
