中文摘要：

以不依赖于培养的16S rDNA-PCR-DGGE技术，评价了石油污染对我国最大的石油污水灌区——沈抚灌区稻田土壤细菌遗传多样性的影响，并对微生物群落中的优势菌群进行了研究。结果表明，沈抚灌区土壤总石油烃（Total petroleum hydrocarbon，TPH）含量为277—5213mgkg^-1干土，TPH在灌区干渠和支渠中的积累和分布趋势大体上是上游地区较严重，下游地区较轻，并且与土壤中有机质含量呈显著正相关（r=0．691，P〈0．05）。在目前的污染程度下，石油污水能够刺激土壤好氧异养细菌（Aerobic heterotrophic bacteria，AHB）的生长，其数量与TPH含量呈显著正相关（r=0．928，P〈0．001），而细菌遗传多样性与TPH含量呈显著负相关（r=-0．715，P=0．013）。DGGE图谱优势条带测序结果表明沈抚灌区土壤细菌群落中的优势菌群为变形细菌（Proteobacteria）β-亚群和γ-亚群的菌种，这些优势菌群的形成可能与石油烃的生物降解有关。

英文摘要：

Effects of petroleum contamination on counts, diversity and dominant populations of bacteria in paddy soils were investigated in the Shenfu Irrigation Zone, the largest zone irrigated with oil-containing wastewater for more than 50 years in Northeast China. Bacterial genetic diversity was determined with 16S rDNA PCR-denaturing gradient gel electrophoresis （ DGGE）. Results show that total petroleum hydrocarbon （TPH） concentration in the paddy soil varied from 277 to 5 213 mg kg^- 1 dry soil. Soil TPH concentration declined along with the distance of the irrigation channel from the water source, showing a gradient from upstream to downstream and was positively correlated with organic matter （ r = 0. 691, p = 0. 057）. At the current pollution level, the paddy soil TPH concentration was positively correlated with the CFU of aerobic heterotrophic bacteria （AHB） （r = 0. 928, p 〈 0. 001 ）. While genetic diversity of the bacteria based on DGGE profiles was negatively correlated with TPH concentration （r = -0. 715, p = 0.013）. Sequence analysis of prominent bands in DGGE profiles show that β and γ subgroups of Group Proteobacteria were dominant in paddy soil of the Shenfu Irrigation Zone, All or some of the populations may play a significant role in metabolizing the petroleum compounds.