【作者】 刘芳；

【导师】 赵吉；

【作者基本信息】 内蒙古大学 ， 微生物学， 2011， 硕士

【摘要】 湿地是自然界中人类重要的环境资源,具有巨大的环境调节功能及生态效益。内蒙古高原湿地资源丰富,但也是最受威胁的生态系统。湿地作为氮素的源、汇或转化器的功能在生态学和环境科学领域日渐受到重视。内蒙古高原湿地资源丰富,也是最受威胁的生态系统,但这个区域中氮素循环微生物群落结构变化分析的研究还是空白。本文以内蒙古高原区域内陆河湿地土壤氨氧化微生物动态变化为切入点,通过16S rDNA-PCR-DGGE技术研究了内蒙古高原锡林河湿地不同土壤的细菌和氨氧化细菌(AOB)的群落结构和遗传多样性,并对AOB中的优势菌群进行测序研究,构建了N-J系统发育树。主要结果如下：从河心底泥(HX)→河边底泥(HB)→低河漫滩(DQ)→高河漫滩(EQ)→典型草原(TN)河流陆向分布的5个样点中,Shannon-wiener Index(H)、Richness(S)、Evenness(E)都呈先增后减的单峰趋势,土壤细菌和AOB群落结构及其多样性呈现明显的湿地过渡带分布特征,表明湿地高度的土壤微生物多样性为该区域巨大的植物生产力提供了基础条件。塔头湿地土壤细菌以及AOB的这些指数均表现为塔头高于塔头间,说明塔头土壤更适合细菌以及AOB的生长。通过对9个湿地土壤样品DGGE图谱进行聚类分析,发现河心底泥(HX)、河边底泥(HB)、低河漫滩(DQ)样点土壤中细菌群落的多样性相似；河心底泥(HX)、河边底泥(HB)样点和围封塔头间湿地(WJ)、放牧塔头间湿地(FJ)长期积水的塔间样地的AOB群落结构图谱可以分别聚为一类,说明水生环境是影响细菌群落结构的重要因素。对AOB的DGGE优势条带切胶测序及系统发育分析发现,β-Proteobacteria占主导地位,大部分为亚硝化单胞菌(Nitrosomonas)和类亚硝化螺旋菌(Nitrosospira-related)。据此推断,河流湿地土壤中,Nitrosomonas为AOB群落中的优势菌。研究结果可以为内蒙古高原湿地土壤微生物研究提供基础数据,并为氮素循环研究提供理论依据。更多还原

【Abstract】 Wetlands are important natural environment of human resources, it has great environmental regulation features and ecological benefits. Though there are rich resources in Inner Mongolia Plateau wetland soil, it is also the most threatened ecosystems which is rarely studied and reported. The function of Wetlands as a nitrogen source, sink or converter in the global biogeochemical cycles has increasingly attracted people’s attention. Though there are rich wetland resources in Mongolian Plateau, it is also the most threatened ecosystems which is rarely studied and reported. The study about the community structure changes of N-cycle bacteria in the area is almost blank.In this paper, we studied the community structure and Genetic diversity of wetland soil bacteria and ammonia oxidizing bacteria (AOB) in Xilin River of Inner Mongolia Plateau by 16S rDNA-PCR-DGGE, and sequenced certain typical dominant AOB groups, constructed the phylogenetic tree. The main results are as follows:Shannon-wiener Index (H)、Richness (S) and Evenness (E) both in bacteria and AOB increased and then decreased from the 5 terrestrial distribution samples:samples of sediment collected in the bottom at the centre river (HX)→samples of sediment collected in the riverside (HB)→samples collected in the low floodplain (DQ)→samples collected in the high floodplain (EQ)→samples collected in the typical steppe (TN), showed that the community structure and diversity of bacteria and AOB had obviously land distribution features. Wetland transition areas of high soil microorganisms diversity, can provide a microbial ecology basis for the high biological productivity in this area.Shannon-wiener Index (H)、Richness (S) in the towertip was higher than the indexes in the sample among towers whether in enclosed or garzing plots. Indicating that the towertip was more sutiable for the aerobic bateria to survive.Cluster analysis of the DGGE patterns demonstrated that the diversity of bacterial in 3 river samples HX, HB, DQ was simple with each other; the AOB in 2 river samples HX, HB and WJ, FJ samples between towers that Perennial flooded can be clustered together, concluded that water environment is a very important factor infect the bacteria’s community structures.From the sequencing of the AOB partial 16srRNA genes fragments and study of phylogenetic tree, we find that the community was dominanted by beta Proteobacteria, most of them were Nitrosospira-related and Nitrosomonas-related sequences, we infered that in the river environment, Nitrosomonas sp. may be the dominant species. Our research can provide basic data for the Inner Mongolia Plateau wetlands nitrogen cycle, contribute to global climate change and provide a theoretical basis for ecological and environmental protection.更多还原