三叶草对重金属镉的富集特性研究

Enrichment Features of Trifolium pratense L. under Cadmium Stress

研究了不同质量浓度镉胁迫下三叶草对重金属的富集特性。结果表明,在试验所设定的镉质量浓度范围内,三叶草的根、茎、叶各部均未出现明显的镉毒害症状,说明三叶草对镉胁迫有一定的耐受性。在不同质量浓度镉胁迫下,三叶草根、茎、叶各部的镉含量均出现了不同程度的变化,不论是地上部分或是地下部分,其富集系数均随着镉质量浓度的增加呈现下降趋势,富集系数均大于1;镉富集的临界含量均大于100μg/g,平均转运系数为1.025 8,其中,当镉质量浓度低于25 mg/L时,三叶草在不同镉质量浓度下的转运系数基本接近1或大于1。说明在一定质量浓度镉胁迫下,三叶草表现出富集植物的特性。

The enrichment features of Trifolium pretense L.under cadmium stress were studied.The results showed that roots,stems and leaves of Trifolium pretense L.did not display obvious poisoning symptoms and had partial tolerance to cadmium stress under certain concentration of Cd.The content of Cd in the three parts of Trifolium pratense L.varied under cadmium stress of different concentration.The bioaccumulation factor of overground part and underground part showed a downward trend with increasing concentration of Cd.The coefficient of enrichment was greater than 1 for all.At different levels the critical content of cadmium enriched by Trifolium pratense L.was greater than 100μg/g and the average transfer coefficient was 1.0258.When the concentration of cadmium was below 25mg/L,the transfer coefficient was close to or greater than 1.The results demonstrated that Trifolium pratense L.had enrichment features under cadmium stress.