磷影响下根际无机砷的形态分布及其对水稻生长的影响

两种有代表性的紫色土的水稻盆栽试验结果表明 ,磷的加入可减轻受砷污染的红紫泥中砷对水稻的毒害 ;但磷的加入会加剧受砷污染的红棕紫泥中砷对水稻的毒害。根际无机砷的形态分布研究表明 :试验土壤上 ,根际砷各形态都比非根际高 ,砷在根际呈富集状态 ;在根际环境的作用下 ,红紫泥中 ,磷的加入加剧了砷由有效态砷 (Al As、Fe As)向相对无效态砷 (O As)转化 ,砷对水稻的毒性减弱 ;红棕紫泥中 ,磷的加入加剧了砷由相对无效态砷Fe As和Al As向有效态砷Ca As和A As(表示水溶态砷及松结合态砷 )的转化 ,砷对水稻的毒性增强

EFFECT OF PHOSPHORUS ON DISTRIBUTION OF INORGANIC ARSENIC FRACTIONS IN RHIZOSPHERE AND GROWTH OF RICE

Pot experiment with rice on two typical purple soils shows that in red purple soil phosphorus could reduce arsenic poisoning to rice, while the effect was just the opposite in red brown purple soil. The research on distribution of arsenic fractions clarifies that there was higher content of arsenic of different fractions in rhizosphere than in nonrhizosphere in two soils, and arsenic existed in an accumulating state in the rhizosphere. In the red purple soil, arsenic was transformed from available arsenic (Fe As, Al As) to relatively inavailable one (O As) when phosphorus was added, thus reducing the biotoxicity of arsenic. While in the red brown purple soil, arsenic was transformed from relatively inavailable arsenic (Fe As, Al As) to available one (Ca As, A As) when phosphorus was added.