摘要
采用营养液培养方法研究了苗期小麦和水稻对硒酸盐(Na2SeO4)和亚硒酸盐(Na2SeO3)的吸收及转运机制.营养液中供给Na2SeO4时,正常培养的水稻地上部和根中硒的含量分别30.3 mg.kg-1和39.0 mg.kg-1,水稻吸收的硒有80%从根转移到了地上部;小麦地上部和根中硒的含量分别为1.76 mg.kg-1和6.99 mg.kg-1,62%从根转移到了地上部.而供给Na2SeO3时,正常培养的水稻地上部和根中硒的含量分别为4.40 mg.kg-1和230 mg.kg-1;小麦地上部和根中硒的含量分别为1.24mg.kg-1和88.3 mg.kg-1,仅有8.2%从根转移到了地上部.缺磷培养对水稻和小麦吸收硒的影响存在差异,与正常培养相比,缺磷培养水稻的地上部、地下部硒含量降低,而小麦的地上部、地下部硒含量增加.小麦根系吸收SeO23-的米氏常数(Km)是水稻的8.7倍,其最大吸收速率(Vmax)比水稻低14%,小麦和水稻对亚硒酸盐的吸收差异主要是根系对SeO32-的亲和力.本研究揭示了水稻和小麦对硒酸盐和亚硒酸盐的吸收和转运机制,为作物强化富硒提供了理论依据.作物吸收的硒酸盐向地上部的转移速率很快,而亚硒酸盐主要累积在根中.
Solution culture experiments were carried out to study the uptake and translocation of selenate （Na2SeO4 ） or selenite （Na2SeO3） by wheat and rice seedlings. When supplied with Na2SeO4 in nutrient solution, the concentrations of selenium （Se） in normal shoots and roots of rice were 30.3 mg·kg^-1 and 39.0mg·kg^-1 respectively, and the absorbed Se was quickly translocated to shoots accounting for 80% of the total uptake. Se concentrations in wheat shoots and roots were 1.76 mg·kg^-1 and 6.99 mg·kg^-1 respectively, accounting for 62% in shoots. However, when supplied with Na2SeO3 , Se concentrations in shoots and roots of rice were 4.40mg·kg^-1 and 230mg·kg^-1 respectively, 1.24mg·kg^-1 and 88.3mg·kg^-1 in shoots and roots of wheat respectively, and only 8.2% was transferred to shoots. The influence of phosphorus （P） starvation on Se uptake was different for rice and wheat seedlings. Comparing to normal plants, the Se concentrations in the shoots and roots of rice under P starvation condition were decreased, however increased for wheat. In Na2SeO3 uptake kinetics, Km of wheat seedlings was 8.7 folds of that of rice, and the affinity of wheat root to selenite was much weaker than that of rice. The Se uptake rate of wheat （ Vmax） was 14% lower than that of rice. The uptake and translocation mechanisms of selenate and selenite by rice and wheat seedlings were revealed. And the results demonstrate that the absorbed selenate is quickly translocated to shoot and selenite is mainly accumulated in root. These results provide basic information for biofortifieation of crops with Se.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2011年第1期284-289,共6页
Environmental Science
基金
公益性行业科研专项(2008030030)
国家科技支撑计划项目(2008BADA4B01)
国家自然科学基金项目(41073094)
