植物对硒的吸收转运和形态转化机制

阐述了植物对不同形态硒的吸收、转运和形态转化机制。植物主要吸收水溶性硒,包括部分有机硒、硒酸盐和亚硒酸盐。多数研究表明植物对硒酸盐的主动吸收是通过高亲和力的硫酸盐转运子完成,最近的研究表明磷酸盐可以调节亚硒酸盐的吸收,磷酸盐转运子在亚硒酸盐的主动吸收过程中有重要作用;植物吸收的硒酸盐很快从根部转移到地上部,在叶片中被还原成亚硒酸盐,进而转化为有机硒化物进入其他组织;而亚硒酸盐及其代谢产物主要积累在根部,极少转移到地上部。进入植物体中的硒转化为含硒氨基酸和硒蛋白参与植物的代谢。

Mechanisms of Selenium Uptake, Translocation and Chemical Speciation Transformation in Plants

In this review, we summarized the uptake, translocation and metabolism mechanisms of selenium (Se) in plants. Water-soluble Se, including selenate, selenite and some organic selenium, was the predominant form taken up by plants. The active uptake of selenate in plant could be mediated by high affinity sulfate transporters. The mechanism of selenite uptake was not well understood, however, recent studies suggested that selenite uptake was probably mediated by Pi transporters. The translocation of Se from root to shoot was dependent on the form of Se supplied. The selenate taken up by plants was readily translocated to the shoots and reduced to selenite in leaves, then converted to organic Se compound. By contrast, most of the selenite taken up by plants in the roots and only a small fraction was translocated to the shoots. Se could be assimilated to seleno amino acids or selenoprotein after plant uptake, and then involved in the metabolism of plants.