宁夏贺兰山东麓荒漠土壤中贫营养细菌及其生态学效应研究
发布时间：2018-09-18 19:37
【摘要】：贫营养微生物存在于一些营养贫瘠的极端环境中,具有独特的生态学意义。荒漠化土壤中存在着一些贫营养细菌,有研究表明,它们在生长过程中会分泌胞外多糖等黏性物质,可以粘结土壤颗粒,稳定表层土壤,改善土壤的理化性质,促进土壤生物结皮形成。本论文采集宁夏贺兰山东麓贫营养环境土壤,对其微生物组成进行分析,对其中贫营养微生物进行分离,并对典型贫营养微生物在荒漠化土壤中的生态学作用进行了研究。论文研究结果如下：(1)采用PCR-DGGE技术对三个典型地点土壤样品的细菌类群结构和多样性进行了研究。结果表明,不同有机质条件下土壤中16S rDNA V3区片段的DGGE带谱之间存在差异,通过DGGE条带的克隆测序比对发现,贺兰山东麓荒漠化贫营养环境中的细菌主要属于放线菌纲(Actinobacteria)、6-变形菌纲(Deltaproteobacteria)和一些未命名的菌种,并且大多数属于不可培养细菌。结合本实验室前期研究结果发现,两种贫营养土壤中的细菌Deltaproteobacteria与 Micromonosporaceae bacterium菌也存在于微生物结皮发育形成初期,推测这两种菌可能与微生物结皮的形成和发育有关。(2)相关性指数分析表明,土壤有机质含量和含水量与土壤微生物生物量及微生物多样性之间的相关性极显著,是影响贫营养环境中微生物种类和数量组成的重要因素。(3)从贫营养土样中分离出5株贫营养微生物,分别编号为P1、P2、P3、P4和P5,经鉴定,P1、P2、P3和P5属链霉菌属,P4菌为枯草芽孢杆菌。P4菌的最适生长温度为37℃,最适pH值在7-8之间,培养基最适含碳量为15 mg/L。(4)P4菌具有很强的溶磷和解钾作用,其生长可以有效改善贫营养土壤肥力,为其他土壤微生物和植物生长提供营养物质。荒漠化土壤喷洒P4菌剂后,土壤的含水量和持水性显著提高,渗水性显著下降,有利于表层土壤水分的保持。
[Abstract]:Nutrient-poor microorganisms exist in some extreme environments with poor nutrition and have unique ecological significance. There are some nutrient-poor bacteria in desertification soil. Some studies have shown that they secrete extracellular polysaccharides and other viscous substances during their growth, which can bind soil particles, stabilize the surface soil, and improve the physical and chemical properties of the soil. Promote the formation of soil biological crust. In this paper, the poor nutritious soil in the eastern foothills of Helan Mountain in Ningxia was collected, its microbial composition was analyzed, the poor nutrient microbe was isolated, and the ecological function of typical poor nutrient microbe in desertification soil was studied. The results are as follows: (1) the bacterial community structure and diversity of soil samples from three typical sites were studied by PCR-DGGE technique. The results showed that there were differences between the DGGE bands of 16s rDNA V3 region in soil under different organic matter conditions. The results of cloning and sequencing of the 16s rDNA V3 region were compared with each other. The bacteria in the desertified and nutritious environment in the eastern foothills of Helan Mountain mainly belong to the (Deltaproteobacteria) of (Actinobacteria) 6-Proteus and some unnamed bacteria, and most of them belong to uncultured bacteria. Combined with the results of our previous study, it was found that the bacteria Deltaproteobacteria and Micromonosporaceae bacterium also existed in the early stage of the formation of microorganism crusts in two kinds of nutrient-poor soils. It is speculated that these two bacteria may be related to the formation and development of microbial crusts. (2) correlation index analysis shows that the correlation between soil organic matter content and water content and soil microbial biomass and microbial diversity is very significant. It is an important factor to affect the species and quantity of microorganisms in the poor nutrition environment. (3) five strains of poor nutrient microbes were isolated from the samples of poor nutrition soil. The optimum growth temperature was 37 鈩，
本文编号：2248920
[Abstract]:Nutrient-poor microorganisms exist in some extreme environments with poor nutrition and have unique ecological significance. There are some nutrient-poor bacteria in desertification soil. Some studies have shown that they secrete extracellular polysaccharides and other viscous substances during their growth, which can bind soil particles, stabilize the surface soil, and improve the physical and chemical properties of the soil. Promote the formation of soil biological crust. In this paper, the poor nutritious soil in the eastern foothills of Helan Mountain in Ningxia was collected, its microbial composition was analyzed, the poor nutrient microbe was isolated, and the ecological function of typical poor nutrient microbe in desertification soil was studied. The results are as follows: (1) the bacterial community structure and diversity of soil samples from three typical sites were studied by PCR-DGGE technique. The results showed that there were differences between the DGGE bands of 16s rDNA V3 region in soil under different organic matter conditions. The results of cloning and sequencing of the 16s rDNA V3 region were compared with each other. The bacteria in the desertified and nutritious environment in the eastern foothills of Helan Mountain mainly belong to the (Deltaproteobacteria) of (Actinobacteria) 6-Proteus and some unnamed bacteria, and most of them belong to uncultured bacteria. Combined with the results of our previous study, it was found that the bacteria Deltaproteobacteria and Micromonosporaceae bacterium also existed in the early stage of the formation of microorganism crusts in two kinds of nutrient-poor soils. It is speculated that these two bacteria may be related to the formation and development of microbial crusts. (2) correlation index analysis shows that the correlation between soil organic matter content and water content and soil microbial biomass and microbial diversity is very significant. It is an important factor to affect the species and quantity of microorganisms in the poor nutrition environment. (3) five strains of poor nutrient microbes were isolated from the samples of poor nutrition soil. The optimum growth temperature was 37 鈩，
本文编号：2248920
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