过量Fe^(2+)胁迫下水稻的养分吸收和分配

Nutrient uptake and partitioning in rice plant under excessive Fe^(2+) stress

采用水培法研究了不同浓度过量Fe2+对水稻生长,地上部及根系的N、P、K、Ca、Mg以及Fe等微量元素吸收及分配的影响.试验结果表明:过量Fe2+胁迫抑制了水稻地上部和根系生长及N、P、Mg的吸收,促进了Cu的吸收.Fe2+浓度保持在一定范围能促进水稻地上部和根系对Ca、Mn的吸收,高浓度Fe2+则会抑制Ca、Mn的吸收.根系的Fe、Cu和Zn含量高于地上部.同时Fe2+胁迫也抑制了P、K、Mg和Zn等有效养分在根系与地上部之间的分配,破坏了养分的分配平衡,加剧了铁毒的发生,这可能是Fe2+胁迫下植株受伤害的机理之一.

Solution culture was carried out to study the uptake and partitioning of nutrients in rice plant under excessive Fe2+ stress. The results indicated that excessive Fe2+ stress reduced N, P and Mg absorption but enhanced Cu absorption. Fe2+ increased the absorption of Ca and Mn at 50 and 150 Fe2+ mg/kg levels, whereas reduced their uptake at Fe2+ levels higher than 150 mg/kg. The concentration of Fe, Cu and Zn in roots were higher than those in shoots. Excessive Fe2+ stress inhibited translocation of nutrients, e.g. P, K, Ca and Mg, from roots to shoots, resulting in nutrient distribution imbalance between shoot and root, which, in turn, caused more sever iron toxicity. Iron toxicity of rice might be ascribed partially to the disturbance of nutrient distribution between shoots and roots brought about by the excessive Fe2+ stress.