Differences in the Rhizosphere Microbial Activity and Community Composition of Commelina communis along a Copper Contamination Gradient

Abstract

We studied the effects of copper (Cu) phytoremediation on microbial community composition under laboratory conditions. A Cu accumulator, Commelina communis, was grown on a soil containing different gradients of Cu. Results showed that the biomass of C. communis grown with Cu differed from that of the control. Concentrations of Cu in the shoots of C. communis were 73.6, 160.9, and 319.1 mg kg⁻¹ under 200, 500, and 1000 mg kg⁻¹ Cu treatments, respectively. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprint analysis revealed that additions of Cu decreased the number of bands in the soil with C. communis or without plants. The principal component analysis explained 52.7% of the variance for the different rhizospheres of soil and Cu treatments in the soil samples. These results indicated significant effects on soil bacteria activity and community composition in the rhizosphere of C. communis and provided a basis for further studies of metal-accumulator plant effects on soil microorganisms.

Keywords:

• Accumulator
• activity
• Commelina communis
• community composition
• copper
• microorganism

Acknowledgments

This work was supported by the National Natural Science Foundation of China (40801195) and the Opening Project of the State Key Laboratory of Soil and Sustainable Agriculture (0812000047).