Abstract: Three habitats of Miscanthus floridulusin Zhejiang Province, i.e., Pb/Zn mine tailings in Huangyan area (W), Pb/Zn mine tailings in Sanmen area (Y), and heavy metals contaminated agricultural field near smelters (N), were chosen as sampling sites, and the microbial basal respiration, microbial biomass carbon and nitrogen, physical and chemical properties, and heavy metals contents in bulk and rhizosphere soils were determined. The results indicated that the microbial basal respiration and microbial biomass nitrogen were significantly higher in rhizosphere soil than in bulk soil (P<0.05), while microbial biomass carbon, except that in site N, had no significant difference between bulk soil and rhizosphere soil (P>0.05). The organic carbon, total nitrogen (except in site Y), and cation exchangeable capacity (except in site N) were lower in rhizosphere soil than in bulk soil, and the total and DTPAextractable Pb, Zn, Cu and Cd were generally lower in rhizosphere soil than in bulk soil. Redundancy discriminant analysis (RDA) showed that the microbial parameters in bulk and rhizosphere soils had definite positive correlations with soil physical and chemical properties, and negative correlations with soil heavy metals contents. Principal components analysis (PCA) and regression analysis also showed that the overall changes in microbial parameters were positively correlated with soil physical and chemical properties (bulk soil:R²=0.653; rizhosphere soil: R²=0.690), and negatively correlated with soil heavy metal contents (bulk soil: R²=0.610; rizhosphere: R²=0.662).

Key words: herbivorous insects, heavy metal, environmental pollution, physiological toxicity, growth