Genetic diversity of microbial communities in farmland soils contaminated with mixed heavy metals
重金属复合污染农田土壤的微生物群落遗传多样性研究

Four soil samples contaminated with the different levels of mixed heavy metals were collected from a nearby smelter and the soil DNA was extracted by FastPrep system from which fragments were amplified. The genetic diversity of the soil microbial communities was analyzed by DGGE (denaturing gradient gel electrophoresis) of a conservative region of 16S rRNA gene. The results indicated that the mixed heavy metal pollution affected soil microbial community diversity, but there were not the simply negative relations between mixed heavy metal contamination and genetic diversity of soil microbial communities, and the largest diversity indexes appeared in the moderate mixed polluted soil. The reason might be that heavy metals changed the competitive relationships among individuals of soil microbial community, which lead to the lose of the dominance of the original predominant populations, or that the bacteria resistant to heavy metals protected other more sensitive ones.