Joint effects of acetochlor and Cu2+ on indigenous bacterial communities in phaeozem
乙草胺铜离子复合污染对黑土农田生态系统中土著细菌群落的影响

Jointly toxic effects of acetochlor and Cu~(2 ) on indigenous bacterial communities in phaeozem were studied using the traditional toxicity assessment methods combined with the modern molecular techniques. It was indicated that acetochlor and Cu~(2 ) had a synergic inhibitory effect on the amount of culture-dependent viable bacteria including nitrogen-fixing bacteria, silicate bacteria and phosphorus-mineralization bacteria, as well as the activity of soil dehydrogenase. The increase in the substrate-induced respiration (SIR) was significantly promoted by the two pollutants. Analyzing the similarity and the banding patterns by the denaturing gradient gel electrophoresis (DGGE) revealed that the joint toxicity of acetochlor and Cu~(2 ) can significantly affect bacterial community structure. Microbial structures of the polluted soils and the clean soil without pesticide application were different, but there was a similarity in microbial structures between the soil with long-term pesticide application and the soil treated simultaneously with acetochlor and Cu~(2 ) under the experimental condition, of which the similarity coefficient was up to 74.1%.