不同栽培条件下印度芥菜对重金属的吸收比较

分别以石英砂(砂培)和潮褐土(土培)为栽培基质,以印度芥菜为供试植物,以巨大芽胞杆菌和胶质芽胞杆菌为强化微生物,开展盆栽模拟试验,探讨印度芥菜在不同栽培基质条件下对土壤中重金属的吸收规律以及微生物对印度芥菜吸收重金属能力的增效.结果表明:砂培条件下印度芥菜对重金属的吸收量远大于土培基质,其中Cd表现最为明显;砂培条件下印度芥菜地上部w(Cd)为土培基质中的10.99倍,w(Pb)为6.19倍,w(Zn)为1.72倍;地下部w(Cd)为土培基质中的33.95倍,w(Pb)为28.04倍,w(Zn)为10.61倍.印度芥菜地下部对重金属的吸收富集能力远高于地上部,约为地上部的1~3倍.经微生物强化处理后,印度芥菜对重金属Cd、Pb、Zn的富集系数分别增加了0.09、0.09和0.12,说明微生物可强化植物对重金属的吸收.印度芥菜对重金属吸收潜力较大,但土壤中重金属的生物有效性限制了植物吸收的效率,因此采用微生物强化植物修复土壤重金属污染意义很大.

Comparative Study of Different Cultivation Conditions on the Absorption of Heavy Metals in Brassica juncea

This research has taken the quartz sand and meadow cinnamon soil as substrates, Brassica juncea as the tested plant, Bacillus megatherium and Bacillus mucilaginous as microorganisms to stimulate the absorption progress of plants to heavy metals in the soil. Based on the pot-cultivation, the heavy metal absorbency of Brassica juncea in different substrates, and the promoting effect of heavy metal absorbency under microbial strengthen were studied. The results showed that the absorption of Brassica juncea to heavy metals in the sand-matrix was much stroger than that in the soil-matrix, especially for Cd. Above the ground, the content of Cd in sand-matrix was 10.99times of that in soil-matrix (Pb, 6.19; Zn, 1.72). Under the ground, the content of Cd in sand-matrix was 33.95times of that in soil-matrix (Pb, 28.04; Zn, 10.61). The heavy metal absorption of underground part was much higher (1-3times) than that of above ground part. After being handled with microbial agents, the indices for Cd, Pb, Zn absorption of Brassica juncea increased by 0.09,0.09and 0.12respectively, which showed that microbial agents can reinforce the plant absorption ability to the heavy metal. Finally, this study showed that Brassica juncea, as an enrichment plant, performs significant heavy metal absorption potential. However, biological effectiveness of heavy metal in soil can reduce the efficiency of phytoextraction, which strengthens the significance of microbial strengthen in the remedy of heavy metal pollution in soil.