The responses of three cultivars of Chinese cabbage (Brassica chmensis L.), one of the main vegetable crops in China, to different ratios of NH4+-N/NO3--N was investigated to find the optimal ratio of ammonium to nitr...The responses of three cultivars of Chinese cabbage (Brassica chmensis L.), one of the main vegetable crops in China, to different ratios of NH4+-N/NO3--N was investigated to find the optimal ratio of ammonium to nitrate for maximal growth and to explore ways of decreasing the nitrate content, increasing nitrogen use efficiency of Chinese cabbage, and determining distributions of nitrogen and carbon. Three cultivars of Chinese cabbage were hydroponically grown with three different NH4+-N/NO3--N ratios (0:10…展开更多
Two japonica rice （Oryza sativa L.） cultivars, Xiushui 48 and S. Andrea, differing in their ability to accumulate Se in the grain （as high as a three-fold difference）, were compared for selenium （Se） accumulatio...Two japonica rice （Oryza sativa L.） cultivars, Xiushui 48 and S. Andrea, differing in their ability to accumulate Se in the grain （as high as a three-fold difference）, were compared for selenium （Se） accumulation in their shoots when their growth media was supplied with different forms of Se. Results indicated that when treated with 0.25μmol L^-1 Na2SeO3, Xiushui 48 accumulation of Se in the shoots was significantly more rapid （P〈0.05） than S. Andrea, probably because of greater Se uptake and transport in Xiushui 48. Xiushui 48 rice seedlings had a higher shoot-Se accumulation rate and absorbed selenocysteine （Se-Cys） more rapidly than S. Andrea seedlings. However, when treated with Se as 0.25μmol L^-1 selenomethionine （Se-Met）, the S. Andrea seedlings＇ accumulation rate was significantly greater （P〈0.05） than that of Xiushui 48. Possibly, the high Se accumulation rate of Xiushui 48 seedling shoots compared to S. Andrea shoots was the result of a higher capacity of Xiushui 48 to transform selenite to organic Se compounds and a higher selenite uptake rate.展开更多
A model for simulating cadmium transport in a soil-plant system was built using a commercial simulating program named Powersim on the basis of input-output processes happening in the soil-plant system. Convective and ...A model for simulating cadmium transport in a soil-plant system was built using a commercial simulating program named Powersim on the basis of input-output processes happening in the soil-plant system. Convective and dispersive transport processes of cadmium in soil profile are embedded. Simulations on a daily base have been done up to a total simulating time of 250 years. Results show that applications of sewage sludge and fertilizer at the simulated rates would only cause slight cadmium accumulations in each layer of the soil, and cadmium accumulation would be levelling off, reaching an equilibrium concentrations layer by layer downward after certain time. The time scale to reach an equilibrium concentration varies from 10 years for the top three layers to over 250 years for the bottom layers. Plant cadmium uptake would increase from 52μg m-2 under initial soil cadmium concentrations to 65μg m-2 under equilibrium soil cadmium concentrations, which would not exceed the maximum allowable cadmium concentration in wheat grains. Main parameters which influence cadmium accumulation and transport in soil are total cadmium input, rainfall, evaporation, plant uptake and soil properties.展开更多
Soils in part of rice production areas have been seriously contaminated by cadmium （Cd）. Rice with high Cd content over allowable limit produced in these areas is widely concerned. Low accumulation varieties can rem...Soils in part of rice production areas have been seriously contaminated by cadmium （Cd）. Rice with high Cd content over allowable limit produced in these areas is widely concerned. Low accumulation varieties can remarkably decrease the Cd content in rice as well as the risk of food safety. The translocation of Cd either from soil to root system or from roots to aboveground parts is identified by a lot of ion transport proteins. Transport efficiency of Cd in some rice varieties is regulated by special metal ionic transporters. However, most varieties transport Cd by cation transporters or universal ionic transporters. Both the expression levels and time of gens controlling ionic transporters directly influence the Cd transport rates inside rice plant and the accumulation amount in different organs. Screening and utilizing specific Cd transport genes are the genetic basis of breeding low accumulation varieties.展开更多
基金1 Project supported by the National Natural Science Foundation of China (No. 30270790).
文摘The responses of three cultivars of Chinese cabbage (Brassica chmensis L.), one of the main vegetable crops in China, to different ratios of NH4+-N/NO3--N was investigated to find the optimal ratio of ammonium to nitrate for maximal growth and to explore ways of decreasing the nitrate content, increasing nitrogen use efficiency of Chinese cabbage, and determining distributions of nitrogen and carbon. Three cultivars of Chinese cabbage were hydroponically grown with three different NH4+-N/NO3--N ratios (0:10…
基金Project supported by the National Natural Science Foundation of China (No. 40371063)the National Key Basic Research Support Foundation of China (No. G1999011808).
文摘Two japonica rice （Oryza sativa L.） cultivars, Xiushui 48 and S. Andrea, differing in their ability to accumulate Se in the grain （as high as a three-fold difference）, were compared for selenium （Se） accumulation in their shoots when their growth media was supplied with different forms of Se. Results indicated that when treated with 0.25μmol L^-1 Na2SeO3, Xiushui 48 accumulation of Se in the shoots was significantly more rapid （P〈0.05） than S. Andrea, probably because of greater Se uptake and transport in Xiushui 48. Xiushui 48 rice seedlings had a higher shoot-Se accumulation rate and absorbed selenocysteine （Se-Cys） more rapidly than S. Andrea seedlings. However, when treated with Se as 0.25μmol L^-1 selenomethionine （Se-Met）, the S. Andrea seedlings＇ accumulation rate was significantly greater （P〈0.05） than that of Xiushui 48. Possibly, the high Se accumulation rate of Xiushui 48 seedling shoots compared to S. Andrea shoots was the result of a higher capacity of Xiushui 48 to transform selenite to organic Se compounds and a higher selenite uptake rate.
基金Project supported by the Chinese Postdoctoral Foundation (No. 10129) and the Swedish Agricultural Science Research Foundation (N
文摘A model for simulating cadmium transport in a soil-plant system was built using a commercial simulating program named Powersim on the basis of input-output processes happening in the soil-plant system. Convective and dispersive transport processes of cadmium in soil profile are embedded. Simulations on a daily base have been done up to a total simulating time of 250 years. Results show that applications of sewage sludge and fertilizer at the simulated rates would only cause slight cadmium accumulations in each layer of the soil, and cadmium accumulation would be levelling off, reaching an equilibrium concentrations layer by layer downward after certain time. The time scale to reach an equilibrium concentration varies from 10 years for the top three layers to over 250 years for the bottom layers. Plant cadmium uptake would increase from 52μg m-2 under initial soil cadmium concentrations to 65μg m-2 under equilibrium soil cadmium concentrations, which would not exceed the maximum allowable cadmium concentration in wheat grains. Main parameters which influence cadmium accumulation and transport in soil are total cadmium input, rainfall, evaporation, plant uptake and soil properties.
基金Supported by the Fundamental Research Funds of Central Welfare Scientific Research Institutes(2013-szjj-lzq-04)the Agroecological Environment Protection Program(2013-072)
文摘Soils in part of rice production areas have been seriously contaminated by cadmium （Cd）. Rice with high Cd content over allowable limit produced in these areas is widely concerned. Low accumulation varieties can remarkably decrease the Cd content in rice as well as the risk of food safety. The translocation of Cd either from soil to root system or from roots to aboveground parts is identified by a lot of ion transport proteins. Transport efficiency of Cd in some rice varieties is regulated by special metal ionic transporters. However, most varieties transport Cd by cation transporters or universal ionic transporters. Both the expression levels and time of gens controlling ionic transporters directly influence the Cd transport rates inside rice plant and the accumulation amount in different organs. Screening and utilizing specific Cd transport genes are the genetic basis of breeding low accumulation varieties.
