Abstract: By using whole genomic 16S rDNA PCR-DGGE and sequencing analysis, this paper studied the responses of bacterial community structure of eight soil samples collected from different sites in China to chlorimuron-ethyl stress under the conditions of acclimation in laboratory. There was a notable alternation in the bacterial community structure of all eight samples during 10 weeks enrichment culture with the application of chlorimuron-ethyl increased from 100 mg·L^-1 to 500 mg·L^-1. By the end of the enrichment culture, the Shannon indices of the bacterial community changed significantly, with most of bacterial populations disappeared. Moreover, there was a convergence in the bacterial community structure of all soil samples. The sequencing of the distinguished bands from the 10th week DGGE profile showed that after 10 weeks culture, the culturable Methylophilus sp. and Beta proteobacterium and unculturable bacteria became dominant groups. In the sixteen dominant groups, 10 of them had a similarity above 97% to the known organic pollutant degrading bacteria in phylogenetic tree, and 5 of the 10 had a similarity above 98% to Methylophilus sp. A bacterial population was obtained, which could degrade 67% of 100 mg·L^-1 of chlorimuron-ethyl within 5 days. The main composition of the bacterial population was Methylophilussp., Comamonas sp., Sphingobacterium sp., and Hydrogenophilus sp.  

Key words: alpine meadow, zokor mounds, vegetation restoration, soil microbial community, Biolog-ECO. 