紫花苜蓿对铜铅复合污染土壤的修复效应研究

Remediation of Cu-Pb Contaminated Soil Using Alfalfa(Medicago Sativa)

通过室内盆栽实验,模拟矿区Cu、Pb复合污染土壤条件下的豆科植物紫花苜蓿(Medicago sativa)生长发育情况,并对紫花苜蓿对污染土壤的修复作用进行了研究。结果表明:低浓度的Cu、Pb复合污染对紫花苜蓿的种子萌发、净光合速率和氮吸收无显著影响,高浓度的复合污染明显抑制紫花苜蓿的生长发育,具有显著的毒害作用。紫花苜蓿对污染土壤中Cu和Pb均具有明显的富集作用,并随浓度的增加而增加,且Cu、Pb均主要累积在植物根部。紫花苜蓿对可交换态、碳酸盐结合态Cu、Pb具有较好的提取作用,并可促进土壤中Cu、Pb向残渣态等生物活性的毒性较低的形态转化。

Based on indoor pot experiments,the growth of alfalfa(Medicago sativa)under Cu/Pb contaminated soil conditions and the effect of alfalfa on contaminated soil were studied. The results showed that the low concentration of Cu and Pb pollution presented no significant effects on seed germination rate,net photosynthetic rate and nitrogen absorption of alfalfa.The high concentration of Cu/Pb pollution significantly inhibited the growth of alfalfa and showed obvious toxic effects on net photosynthetic rate and nitrogen absorption. Alfalfa could absorb Cu and Pb from polluted soils along with the increase of Cu and Pb concentration. Most of copper and lead accumulated in plant roots. Alfalfa was proved to be effective for taking up exchangeable and carbonate-bound Cu and Pb. In addition,the transformation of Cu and Pb into residual and other low-toxic morphology was observed with alfalfa remediation.