镉在水稻根际的生物有效性

Cadmium Bioavailability in Rhizosphere of Paddy Soil

综合介绍了水稻根际土壤中的 pH值、Eh值、有机质和微生物、其它金属元素及根分泌物等因素同镉的生物有效性之间的关系。提出水稻根系具有泌氧能力 ,使其根际微环境呈氧化状态。因而 ,土壤溶液中一些还原性物质被氧化 ,如Fe2 +、Mn2 +形成的氧化物在根表沉积成胶膜。胶膜及其根际环境对水稻吸收镉都有一定的影响。

It was demonstrated that bioavailability of cadmium is related with pH, Eh, microorganisms, and other elements in rhizosphere of paddy soil. The rice roots can also excrete oxygen into rhizosphere of paddy soil, leading rhizosphere to oxidation. Several reducers could be oxidized in the condition, such as Fe2+、Mn2+, forming an oxidic plaque on rice root surface. Besides plaque and rice rhizosphere, the environment that affects Cd uptake by root, other factors affecting Cd bioavailability were also mentioned in the present paper.