硅对水稻吸收镉的影响

Effect of silicon on cadmium uptake by rice

通过盆栽试验,以水稻土为供试土壤,采用完全因素试验设计方法,研究硅对土壤中外源镉的活性及其对水稻吸收镉的影响。结果表明,外源镉的添加量越大,水稻根、茎叶和糙米中镉含量越大;在外源镉的添加量为2和5 mg.kg-1时,施硅可降低水稻根、茎叶和糙米中的镉含量;随着施硅量的增加,水稻各部位的镉含量呈现降低趋势,且水稻根部和茎叶的镉含量比例上升,糙米的镉含量比例减少;土壤中的可交换态、碳酸盐结合态镉含量呈降低趋势,铁锰氧化物态、有机结合态和残渣态镉含量呈增加趋势。硅降低土壤中镉对水稻毒害的机制之一是硅改变了土壤中镉的形态,降低了镉的活性和生物有效性。

By pot experiment, rice soil was used for test soil, using the complete factor experimental design method to study the effect of silicon on the activity of exogenous cadmium and cadmium uptake by rice. The results showed that the amounts of exogenous cadmium were greater, the contents of cadmium in the roots, the stems and leaves and the unpolished rice were greater; When the amount of exogenous cadmium was 2 and 5 mg·kg-1, silicon could reduce the contents of cadmium in rice roots, stems and leaves, and unpolished rice; With the amount of silicon was increasing, the contents of cadmium in different parts of rice presented reducing tendency, and the ratio of cadmium content in roots and stems and leaves of rice was rised, the ratio of cadmium content in unpolished rice was reduced; The contents of exchangeable and carbonate-bound cadmium showed the decreased tendency, the contents of Fe-Mn oxide bound cadmium, organic bound and residual cadmium showed the increased tendency. One of the possible mechanisms of silicon-enhancement of resistance to Cd toxicity was that silicon altered the Cd forms in soil, resulting in the reduction of activity and bioavailability Cd.