肠杆菌FM-1强化积雪草修复镉污染土壤机理

Improvement of cadmium-contaminated soil phytoremediation by Centella asiatica L. through bioaugmentation of Enterobacter sp. FM-1

分析了肠杆菌FM-1的耐镉性及促生特性,并研究了肠杆菌FM-1对矿山型和非矿山型积雪草镉富集及根际土壤pH值的影响.结果表明,肠杆菌FM-1对镉有较强的耐受性,其分泌的吲哚乙酸含量,铁载体A/Ar值和溶磷能力分别达到(72.85±0.62)mg/L,0.21±0.01和(143.33±2.13)mg/L,表明肠杆菌FM-1具有良好的促生能力.将肠杆菌FM-1接种于采自广西柳州泗顶铅锌矿周边4种类型的土壤中,均不同程度提高了矿山型和非矿山型积雪草对镉的富集.其中,下游区土壤接种肠杆菌FM-1后,矿山型积雪草茎和叶中镉含量分别增加了87.90%～161.84%和21.85%～76.42%,非矿山型叶片中的镉含量增加了5.84%～35.20%.研究表明肠杆菌FM-1促进了积雪草对镉的富集.同时,肠杆菌FM-1的添加在一定程度上影响了积雪草根际土壤的pH值,显著降低了下游区矿山型积雪草根际土壤中的pH值.

This study analyzed the bacteria tolerance to cadmium and plant growth-promoting substances produced by Enterobacter sp.FM-1.Also,examined the potential of Enterobacter sp.FM-1to assist in cadmium accumulation for Centella asiatica L.and pH value in rhizosphere soil.The results indicated that Enterobacter sp.FM-1had a relatively high cadmium tolerance.Also,the results showed that indole-3-acetic acid,siderophore parameter(A/Ar)and soluble phosphate ability produced by Enterobacter sp.FM-1were(72.85±0.62)mg/L,0.21±0.01and(143.33±2.13)mg/L,respectively,which indicated that bacteria had an excellent plant growth-promoting ability.Meanwhile,inoculation with Enterobacter sp.FM-1in the four types of cadmium-contaminated soils which were collected in Siding lead-zinc mining area,increased the accumulation of cadmium in both two types of C.asiatica L.in different degrees.For instance,inoculation with Enterobacter sp.FM-1in the downstream area soil condition,the cadmium contents in the stems and leaves of mine-type C.asiatica L.increased87.90%~161.84%and21.85%~76.42%,respectively.Meanwhile,the cadmium contents in the leaves of non-mine type C.asiatica L.increased5.84%~35.20%.Hence,inoculation with Enterobacter sp.FM-1significantly increased the accumulation of cadmium in C.asiatica L.Furthermore,inoculation with Enterobacter sp.FM-1had influenced the pH value in rhizosphere soil of C.asiatica L.Especially for mine-type C.asiatica L.,pH value in rhizosphere soil of downstream area soil condition decreased significantly.