Effects of Miscanthus floridulus inhabitation on microbial community structure in mine tailings.

Five sampling sites of mine tailings inhabited by Miscanthus floridulus with the coverage of 0,17%,41%,71%,and 89% were selected to analyze the dynamics of microbial community structure and its relationships with mine tailings’ physical and chemical properties,heavy metals contents,and plant biomass. With the inhabitation of M. floridulus,the mine tailings’ organic carbon,total nitrogen,total phosphorus,NH+4-N,NO-3-N,and available phosphorus contents,aggregate stability,and maximum water-holding capacity increased significantly,but the total and DTPA-extractable heavy metals contents significantly decreased. The principal component analysis indicated that the microbial community structure changed significantly with the inhabitation of M. floridulus. The Gram-positive bacterial fatty acids,Gram-negative bacterial fatty acids,fungal fatty acid,actinomycete fatty acid,mycorrhizal fatty acids(16∶1ω5c and 20∶3ω3) ,algal fatty acids,and microbial community diversity(Shannon-Wiener index) all increased significantly and had significant positive correlations with the mine tailings’ total nitrogen,NO-3-Nand available phosphorus contents,aggregate stability,and the aboveground and belowground biomass of M. floridulus. Only the Gram-negative bacterial and mycorrizal phospholipid fatty acids were negatively correlated with mine tailings’ DTPA-extractable Cu content.