EFFECTS OF MANGANESE POLLUTION ON SOIL MICROBIAL COMMUNITY FUNCTION AND PLANT GROWTH

摘要

We explored the effects of manganese pollution on soil microbial community and plant growth to understand how heavy-metal pollution of soils impacts soil microorganisms, and to test whether changes in soil microbiota could be used as an indicator for heavy-metal pollutions. We grew Chinese cabbage plants in manganese-treated soils in a pot experiment. The function of soil microbial community was analysed using the Biolog ECO technique. Soil microbial community principal component analysis showed that there were significant differences in microbial communities between manganese-contaminated soil and normal soil (P < 0.01). The main carbon source that differed among the treatments was sugar, followed by polymers. When the concentration of soil Mn~(2+) was greater than 300 mg kg~(-1), the variation of typical variables (e.g. dispersion) increased and the stability of the soil microbial community decreased. Microbial community diversity analysis showed that Mn~(2+) contaminated soil had a significant effect on the Mcintosh uniformity index of soil microbes (P < 0.01). The Shannon richness index showed that soil microbial richness was promoted when soil Mn~(2+) concentration was applied in the range of 250-350 mg kg~(-1). Pot experiments showed that when the concentration of Mn~(2+) added into the soil was greater than 250 mg kg~(-1), the growth of plants was affected, and the final biological yield was significantly reduced.