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对重庆市凉风垭地区一具有天然气泄漏的菜园土壤进行采样,利用16S rDNA克隆文库研究了该菜园表层及底层土壤样品中甲烷氧化细菌的群落结构,以期了解甲烷泄漏地区甲烷氧化菌的丰度、结构和组成状况,为深入探讨甲烷在该地区的循环及甲烷泄漏对环境的影响奠定基础。DNA序列分析结果显示,该天然气富集区上覆菜园地土壤中Ⅰ型甲烷氧化细菌以甲基细菌属(Methylobacter)占绝对优势,在底层样品与表层样品中所占比例存在较大差异,且底层样品中Ⅰ型甲烷氧化菌的多样性指数(1.99)比表层样品中的多样性指数(1.3)高。Ⅱ型甲烷氧化细菌仅在底层样品CD1中检测到,以甲基孢囊菌属(Methylocystis)占优势,其多样性指数为2.07,种类较Ⅰ型种类要多,这可能暗示Ⅱ型甲烷氧化细菌更能适应在土壤底层低氧、高浓度CH_4条件下生存。同时,系统发育树分析显示,大部分菜园底层土壤样品中的Ⅰ型甲烷氧化细菌序列无法同已知的甲烷氧化细菌种属聚在一起,暗示该天然气富集区上覆菜园土壤中甲烷氧化细菌具有特殊性。由于Ⅰ型和Ⅱ型甲烷氧化菌对CH_4的亲和力以及对CH_4氧化能力的差异,天然气富集区甲烷氧化菌的群落结构研究对深入了解陆地生态系统CH_4代谢具有重要意义。
A sample of garden soil with natural gas leakage in the Liangfangya area of Chongqing was sampled. The 16S rDNA clone library was used to study the community structure of methanotrophs in the surface and bottom soil samples in order to find out the abundance of methane oxidizing bacteria , Structure and composition of coal, which lays the foundation for further exploration on the impact of methane on the environment in the region due to circulation and methane leakage. The results of DNA sequence analysis showed that Methylobacter was the dominant type I methanotroph in the soil above the vegetable garden in the area rich in natural gas, and there was a big difference between the proportion of the bottom and the surface samples The diversity index (1.99) of type I methanotrophs in the bottom samples was higher than the diversity index (1.3) in the surface samples. Type II methanotrophs were only detected in the bottom sample CD1, with Methylocystis predominating, with a diversity index of 2.07 and more species than type I, which may suggest that type II methanotrophs More adapted to the bottom of the soil hypoxia, high concentrations of CH_4 survival conditions. Meanwhile, phylogenetic tree analysis showed that the sequence of type I methanotrophs in the soil samples of most of the vegetable gardens could not be clustered with the known species of methanotrophs, suggesting that the methane-oxidizing bacteria Has particularity. Due to the CH_4 affinity of type I and type II methanotrophs and the difference in CH_4 oxidative capacity, the study on the community structure of methanotrophs in gas-rich areas is of great significance for understanding the CH_4 metabolism in terrestrial ecosystems.