侧孢芽孢杆菌对锌尾矿先锋植物富集Zn、Cd能力的影响

Effect of Bacillus laterosporus on enrichment of Zn and Cdin pioneer plants in zinc tailings

采用郴州柿竹园废弃锌尾矿库上生长的4种先锋植物(小蓬草、肾蕨、长芒草和小蓼)进行野外实验,分别测定了地上部位、地下部位及植物根系周围土壤中的Zn、Cd含量。结果表明:添加侧孢芽孢杆菌菌剂后,小蓬草对重金属Zn的富集系数以及转移系数大于Cd,而长芒草对重金属Cd的富集系数和转移系数大于Zn;肾蕨富集重金属Zn的能力几乎不变,小蓼对重金属Zn的富集系数在添加10 g侧孢芽孢杆菌时达到峰值1.6;在菌剂添加量为10 g时,肾蕨转移重金属Cd的能力提升效果最显著,转移系数达到了原来的4~6倍;除了小蓼之外,其他3种先锋植物在施加10~20 g侧孢芽孢杆菌时对土壤中重金属的富集能力较强;富集转移重金属Zn、Cd能力排序为:肾蕨>小蓼>长芒草>小蓬草。

Field experiments was carried out with four pioneer plants(Conyza canadensis(Linn.)Cronq,Nephrolepis auriculata(L.)Trimen,Stipa bungeana Trin and Polygonim minus Huds)on the abandoned zinc tailings pond in Shizhuyuan,Chenzhou.The contents of Zn and Cd in soil overground,underground and around plant roots were measured respectively.The results showed that after adding Bacillus laterosporus,the enrichment coefficient and transfer coefficient of Zn for Conyza canadensis(Linn.)Cronq were higher than those of Cd,while the enrichment coefficient and transfer coefficient of Cd for Stipa bungeana Trin were higher than those of Zn.The ability of Nephrolepis auriculata(L.)Trimen to enrich Zn was almost unchanged.When 10 g Bacillus laterosporus was added,the enrichment coefficient of Zn for Polygonim minus Huds reached a peak value of 1.6.When the addition of bacterial agent was 10 g,the ability of Nephrolepis auriculata(L.)Trimen to transfer heavy metal Cd was significantly improved,and the transfer coefficient reached 4~6 times of the original value.Except Polygonim minus Huds,the other 3 pioneer plants had a strong ability to enrich heavy metals in soil when 10~20 g Bacillus laterosporus was added.The ability of enriching and transferring heavy metals Zn and Cd was ranked as follows:Nephrolepis auriculata(L.)Trimen>Polygonim minus Huds>Stipa bungeana Trin>Conyza canadensis(Linn.)Cronq.