内蒙古不同类型草地土壤微生物多样性及群落结构研究

发布时间：2018-04-17 09:22

本文选题：草地类型 + 微生物数量　；参考：《内蒙古大学》2017年硕士论文

【摘要】：土壤是一个高度动态和复杂的环境,土壤微生物对环境变化的高度敏感性使其成为草地生态健康评价的重要指标。近些年来,内蒙古草地破坏严重,探究土壤微生物在草地中的分布规律及其与土壤理化性质的关系并找出主要驱动因子可以指示草地生态系统的健康,为未来内蒙古不同类型草地的恢复和生态服务功能的实现提供一定的理论依据。本研究选择内蒙古三种代表草地—荒漠草地、典型草地、草甸草地为研究对象,分析了各草地土壤微生物数量、功能多样性、群落结构的变化规律及与土壤理化性质的相关性,找出影响细菌群落分布的主要驱动因子,获得的主要结论如下:(1)利用平板计数法测定土壤可培养微生物数量表明:细菌数量为2.75×10~6～11.1×10~6CFU/g 干土,放线菌数量为 6.1×10~5～2.1×10~6CFU/g 干土,真菌数量为1.8×104～1.O×10~5CFU/g干土。细菌、真菌、放线菌数量变化趋势为荒漠草地典型草地草甸草地。相关性分析发现,细菌、真菌、放线菌数量与pH值、砂砾含量呈负相关,与其他理化因子呈正相关。荒漠草地中放线菌、真菌与总氮含量显著正相关;典型草地中细菌数量与含水量、pH、有机碳、总氮显著相关;草甸草地中放线菌与有机碳、总氮、粗粉粒相关,真菌则与营养元素和机械组成显著相关。(2)利用Biolog-ECO方法测定土壤微生物功能多样性表明:从荒漠草地到草甸草地,微生物对各种碳源的利用量、利用种类是增加的。碳源利用种类由没有偏好转向氨基酸、酚类、胺/氨类、羧酸类碳源优势。丰富度指数、优势度指数、均匀度指数变化范围为3.08～3.87、0.91-0.97、0.76～2.98,均表现出草甸草地最高,荒漠草地最低的变化趋势。相关分析表明,丰富度指数与除含水量外的其他因子显著相关;优势度指数与各因子显著相关。而均匀度与含水量、机械组成有显著的相关性。荒漠草地的均匀度与碳氮比显著正相关;典型草地的优势度与粗粉粒含量正相关;草甸草地的优势度、均匀度与细粘粒正相关。(3)利用高通量测序方法测定土壤微生物细菌群落结构表明:细菌优势门类主要有放线菌门、酸杆菌门、变形菌门、绿弯菌门、芽单胞菌门,占比分别为 25.8%～40.7%、13.5%～36.4%、10.9%～23.3%、9.3%～15.0%、2.7%～6.1%,并且疣微菌门、装甲菌门在三种草地间具有显著差异。统计各草地共有和独有种类数目发现,科水平之前典型草地与荒漠草地细菌类群构成更为相似,科水平后典型草地与草甸草地的构成更为接近,说明典型草地是荒漠草地和草甸草地的过渡地带。RDA分析发现,影响细菌群落分布的理化因子中,机械组成是影响三种草地细菌群落结构分布的主要驱动因子。
[Abstract]:Soil is a highly dynamic and complex environment, and the high sensitivity of soil microorganisms to environmental changes makes it an important indicator of grassland ecological health evaluation.In recent years, grassland in Inner Mongolia has been seriously damaged. The distribution of soil microbes in grassland and its relationship with soil physical and chemical properties are studied and the main driving factors are found to indicate the health of grassland ecosystem.It provides some theoretical basis for the restoration of different types of grassland and the realization of ecological service function in Inner Mongolia in the future.In this study, three representative grasslands in Inner Mongolia, desert grassland, typical grassland and meadow grassland, were selected as the research objects. The changes of soil microbial quantity, functional diversity, community structure and their correlation with soil physical and chemical properties were analyzed.The main driving factors affecting the distribution of bacterial community were found out. The main conclusions were as follows: 1) the number of culturable microorganisms in soil was determined by plate counting method. The results showed that the number of bacteria was 2.75 脳 10 ~ (10) ~ (611.1) 脳 10~6CFU/g dry soil, and the number of actinomycetes was 6.1 脳 10 ~ (10) (52.1 脳 10~6CFU/g) dry soil.The number of fungi was 1. 8 脳 10 ~ 4 and 1. 0 脳 10~5CFU/g dry soil.The change trend of bacteria, fungi and actinomycetes is desert grassland, typical grassland, meadow grassland.Correlation analysis showed that the number of bacteria, fungi and actinomycetes was negatively correlated with pH value and gravel content, but positively correlated with other physical and chemical factors.Actinomycetes in desert grassland, fungi and total nitrogen content were positively correlated; bacteria quantity was significantly correlated with pH, organic carbon and total nitrogen in typical grassland; actinomycetes were correlated with organic carbon, total nitrogen and coarse powder in meadow grassland.Fungi were significantly related to nutrient elements and mechanical composition. (2) Biolog-ECO method was used to determine the functional diversity of soil microorganisms. The results showed that the utilization of various carbon sources by microorganisms increased from desert grassland to meadow grassland.The carbon source utilization changed from no preference to amino acid, phenols, amines / amines and carboxylic acids.The variation range of richness index, dominance index and evenness index was 3.08 ~ 3.87 ~ 0.91-0.977 ~ 0.76 ~ 2.98, which showed that meadow grassland was the highest and desert grassland was the lowest.Correlation analysis showed that the richness index was significantly correlated with other factors except water content, while the dominance index was significantly correlated with each factor.There is a significant correlation between evenness and water content and mechanical composition.The evenness of desert grassland was positively correlated with the ratio of carbon to nitrogen, the dominance of typical grassland was positively correlated with the content of coarse silt, the dominance of meadow was significant.High throughput sequencing method was used to determine the microbial community structure of soil microbes. The results showed that the dominant species of bacteria were actinomycetes, acidobacterium, Proteomycetes, Chlorophyta, Bacillus spp., and Bacillus spp.The ratio of 25.80.7and 13.56.4was 10.9 and 23.39.3and 15.02.70.The verruca microphylum and armored microphylum were significantly different between the three grasslands.It was found that the bacterial composition of the typical grassland was more similar to that of the desert grassland before the family level, and the composition of the typical grassland and the meadow after the family level was more similar to that of the meadow.The results showed that the typical grassland was the transition zone between desert grassland and meadow grassland. RDA analysis showed that among the physicochemical factors affecting the distribution of bacterial communities, mechanical composition was the main driving factor affecting the distribution of bacterial communities in the three grasslands.
【学位授予单位】：内蒙古大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S812.2

【相似文献】