不同相伴阴离子对镉污染红壤微生物区系及群落功能多样性的影响

通过外加醋酸镉和氯化镉的室内培养试验研究了不同相伴阴离子对镉污染红壤中微生物区系及群落功能多样性的影响 .结果表明 :在相同镉浓度下相伴OAc-对镉污染红壤的细菌、放线菌和真菌数量及微生物群落功能多样性的抑制作用大于相伴Cl-.统计分析显示 ,在供试红壤中OAc-与Cl-对其微生物区系及微生物群落代谢剖面 (AWCD值 )、Shannon指数的影响均达到显著差异 (P <0 0 5 ) ,且在红砂土上表现更为明显 .外加醋酸钾和氯化钾的培养试验结果表明 ,阳离子为钾时 ,相伴OAc-与Cl-对红壤微生物区系结构及群落功能多样性没有产生明显抑制作用 ,相伴OAc-甚至存在一定的刺激作用 .可见 ,相伴OAc-对镉污染红壤微生物的毒害作用大于相伴Cl-,其原因并非是阴离子本身的毒性效应 ,而镉的生物有效性变化可能是不同相伴阴离子镉盐导致毒性差异的原因之一 .

Influence of accompanying anions on microbial populations and functional diversity of microbial communities in red soils amended with cadmium

A laboratory incubation experiment was conducted to evaluate the influence of accompanying anions on microbial populations and functional diversity of microbial communities in red soils amended with cadmium. The results indicated that the reduction of the number of soil bacteria,with application of cadmium acetate was more significant than that of cadmium chloride at all the tested levels. Another laboratory incubation experiment was carried out to argue the effect of associated anions on microbial populations and communities functional diversity in red soil added with potassium both acetate and chloride. Its result demonstrated that the two accompanying anions have no negative effect on soil microbial parameters. Instead, accompanying acetate anion increased number of soil bacteria, actinomycetes and fungi, improved structure of microbial communities. The available cadmium content in red soils polluted by cadmium acetate wes higher than those by cadmium chloride. Thus it can be seen that difference between available cadmium contents as the resuts of different accompanying anions could be one of the factors determining their relative toxicity to soil microbial populations and functional diversity of microbial communities.