鄱阳湖典型湿地土壤微生物群落特征及对环境变化的响应研究

发布时间：2018-06-28 02:32

本文选题：土壤微生物群落 + 植物群落　；参考：《江西师范大学》2017年硕士论文

【摘要】：土壤微生物是湿地生态系统中较为活跃的重要组成部分,对环境变化极为敏感。温度、水分、基质有效性等是湿地生态系统土壤微生物3个重要影响因子,本研究在鄱阳湖典型湿地—南矶湿地国家级自然保护区,沿水位梯度采集湖滨高滩地(狗牙根)、挺水植物区(芦苇、南荻和菰)、湿生植物区(苔草和咺草)、沉水植物区(黑藻)共计7种植物群落类型下的表层土壤样品,并对其中3种优势植物群落土壤样品设置不同温度、水分处理,通过室内培养与微生物分析,以阐明鄱阳湖典型湿地土壤微生物群落特征及其对温度、水分、基质有效性等环境变化的响应,为进一步揭示气候变化对鄱阳湖湿地碳氮等生物地球化学循环的影响与机理提供基础数据。主要研究结果如下:(1)变形菌门(Proteobacteria)、酸杆菌门(Acidobacteria)、绿弯菌门(Chloroflexi)和放线菌门(Actinobacteria)等是鄱阳湖典型湿地优势微生物群落组成。(2)自湖滨高滩地至沉水植物区,水分条件或空间位置相近的土壤微生物群落组成可能具有更大的相似性,如南荻、菰、咺草和黑藻群落的微生物群落结构相近,芦苇和苔草的微生物群落结构也相对较近,南荻和狗牙根的微生物群落结构差异最大;微生物群落相对丰度也随群落类型的变化存在一定的差异。(3)在土壤基质有效性基本没有发生变化的情形下(培养初期),温度和水分是影响土壤微生物群落的主导环境因子;不同温度环境下土壤微生物群落丰度与多样性均随土壤水分而发生一定的变化,但变化趋势不具有一致性,此外,温度、水分变化并没有改变优势微生物群落的种类,仅改变了微生物群落的相对丰度。(4)随着土壤有机碳的分解从早期进入中期直至末期,易分解有机碳基本消耗完,难分解有机碳越来越富集,土壤微生物赖以生存的基质有效性下降,群落结构产生了较大变化。微生物丰富度前5位的细菌由初期和中期的“变形菌门(Proteobacteria)、酸杆菌门(Acidobacteria)、绿弯菌门(Chloroflexi)、硝化螺旋菌门(Nitrospirae)、浮霉菌门(Planctomycetes)”变成了“变形菌门(Proteobacteria)、酸杆菌门(Acidobacteria)、厚壁菌门(Firmicutes)、绿弯菌门(Chloroflexi)、硝化螺旋菌门(Nitrospirae)”。此外,放线菌门(Actinobacteria)与疣微菌门(Verrucomicrobia)细菌也明显增加。
[Abstract]:Soil microorganism is an important part of wetland ecosystem, which is sensitive to environmental changes. Temperature, moisture and substrate availability are three important influencing factors of soil microorganism in wetland ecosystem. This study was conducted in the National Nature Reserve of Nanji Wetland, a typical wetland in Poyang Lake. The topsoil samples of 7 plant community types were collected along the gradient of water level in the lakeshore high beach (dogtooth), the octopus plants (Reed, Amur and Zizania latifolia), the wet plant area (Carex spp and Carex sinensis), and the submerged plant area (black algae). The soil samples of three dominant plant communities were treated with different temperatures and moisture. The characteristics of soil microbial communities and their temperature and moisture content in typical wetland of Poyang Lake were elucidated by indoor culture and microorganism analysis. The response to environmental changes such as matrix availability provides basic data for further revealing the effects and mechanisms of climate change on biogeochemical cycles such as carbon and nitrogen in Poyang Lake wetland. The main results are as follows: (1) Proteobacteria, (Acidobacteria), (Chloroflexi) and (Actinobacteria) (Actinomycetes) are the dominant microbial communities in typical wetland of Poyang Lake. The composition of soil microbial communities with similar water conditions or spatial positions may be more similar, for example, the microbe community structure of Amur, Zizania latifolia, Carp and Black algae communities is similar, and the community structure of Reed and Carex spp is also relatively close. The difference of microbial community structure between Amur and Doggopodium chinensis was the biggest. The relative abundance of microbial community also varies with the community type. (3) temperature and moisture are the dominant environmental factors affecting soil microbial community under the condition that the availability of soil substrate does not change basically (at the initial stage of culture); The abundance and diversity of soil microbial communities varied with soil moisture, but the variation trend was not consistent. In addition, the variation of temperature and water did not change the species of dominant microbial communities. Only changed the relative abundance of microbial community. (4) with the decomposition of soil organic carbon from the early to the middle to the end, easy to decompose organic carbon consumption, difficult to decompose organic carbon more and more enriched, The availability of substrates on which soil microorganisms depend for survival decreased, and the community structure changed greatly. The top five bacteria in microbial richness changed from "Proteobacteria, (Acidobacteria), of Lexi, Nitrospirae, Planctomycetes" to "Proteobacteria, (Acidobacteria), Firmicutes, (Acidobacteria),." "Chloroflexi, Nitrospirae". In addition, actinomycetes (Actinobacteria) and Verrucomicrobia bacteria also increased significantly.
【学位授予单位】：江西师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S154.3

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