Microbial abundance and diversity during phytoremediation of military site

摘要

This work was performed to investigate the microbial abundance and diversity during the phytoremediation with barnyard grass (Echinochloa crysgalli) and Indian mallow (Abutilon avicennae) in military site contaminated with heavy metals (<500 mg Pb/kg, <30 mg Cd/kg, <200 Cu/kg, and <100 mg Zn/kg). The concentrations of total, exchangeable and soluble metal were significantly lower in barnyard grass soil than in Indian mallow soil. Soil microbial activities of rhizosphere soils were 2 to 10 folds higher than those of bulk soils. However, soil microbial activities showed similarities between the rhizosphere of barnyard grass and Indian mallow. 16S rDNA fragments amplified by PCR from bulk soil and rhizosphere soil bacterium DNA were analyzed by denaturing gradient gel electrophoresis (DGGE). PCR-DGGE patterns observed for rhizosphere soils were more complex than those obtained from the bulk soil. The Shannon-Weaver index of diversity (H) was higher in the rhizosphere of Indian mallow than in the rhizosphere of barnyard grass. The DGGE fingerprints showed plant-dependent shifts in the relatively abundance of bacterial populations in the rhizosphere soils.