水稻对土壤中环境重金属激素铅的吸收效应及污染防治

Phyto-availability of Environmental Hormone Pb in Soil and Its Effectiveness in Soil Remediation

土壤中重金属元素铅作为一种危害严重的环境激素物质 ,能导致动物和人体各种生殖、生理异常。水稻盆栽试验表明 ,当土壤中加入不同比例的铅时 (0～ 40 0 0mg/kg) ,基本没有观察到铅对水稻的毒害病症 ,铅对水稻的生长发育没有明显的宏观影响。但微区调查揭示 ,水稻对土壤中的铅具有强烈的吸收性 ,并可残留在水稻的各个部位 ,且吸收量随土壤中铅添加量的增加而提高 ;其中根系的吸收性最强 ,是秸杆、籽实的几十至几千倍 ,表明水稻根系为秸杆、籽实对铅的吸收提供了良好的屏障。运用根系对土壤中铅的特殊吸收性 ,可以在铅污染的土壤区通过自然作物栽培 ,并将作物根系从土壤中清除的方法 。

Lead (Pb) acts as one of the estrogens and poses serious risk to human and animal bodies, resulting in procreant anomalies, such as maladjustment of incretion, weakening of procreation function and descending of genital immunity. This paper reports on the potted plant experiments of paddies. The results show that this kind of crop did not indicate any macro toxic symptoms within the range of Pb concentrations of 0 4,000 mg/kg in soils. Meanwhile, it is found that lead in soils is easily absorbed by the crop and remains in the different parts of the plant and statistically, Pb contents of the crop are positively correlated to the counterpart soils. The results also show Pb contents in roots are the highest of all, being tens to thousands times higher than in straw and seeds, implying the barrier action of roots of paddies for Pb absorption of straw and seeds. It is accordingly suggested that heavy metals such as Pb in soil can be decreased gradually by planting paddies through removing the roots.