【摘要】：貧營養(yǎng)微生物存在于一些營養(yǎng)貧瘠的極端環(huán)境中,具有獨特的生態(tài)學意義�；哪寥乐写嬖谥恍┴殸I養(yǎng)細菌,有研究表明,它們在生長過程中會分泌胞外多糖等黏性物質,可以粘結土壤顆粒,穩(wěn)定表層土壤,改善土壤的理化性質,促進土壤生物結皮形成。本論文采集寧夏賀蘭山東麓貧營養(yǎng)環(huán)境土壤,對其微生物組成進行分析,對其中貧營養(yǎng)微生物進行分離,并對典型貧營養(yǎng)微生物在荒漠化土壤中的生態(tài)學作用進行了研究。論文研究結果如下：(1)采用PCR-DGGE技術對三個典型地點土壤樣品的細菌類群結構和多樣性進行了研究。結果表明,不同有機質條件下土壤中16S rDNA V3區(qū)片段的DGGE帶譜之間存在差異,通過DGGE條帶的克隆測序比對發(fā)現(xiàn),賀蘭山東麓荒漠化貧營養(yǎng)環(huán)境中的細菌主要屬于放線菌綱(Actinobacteria)、6-變形菌綱(Deltaproteobacteria)和一些未命名的菌種,并且大多數(shù)屬于不可培養(yǎng)細菌。結合本實驗室前期研究結果發(fā)現(xiàn),兩種貧營養(yǎng)土壤中的細菌Deltaproteobacteria與 Micromonosporaceae bacterium菌也存在于微生物結皮發(fā)育形成初期,推測這兩種菌可能與微生物結皮的形成和發(fā)育有關。(2)相關性指數(shù)分析表明,土壤有機質含量和含水量與土壤微生物生物量及微生物多樣性之間的相關性極顯著,是影響貧營養(yǎng)環(huán)境中微生物種類和數(shù)量組成的重要因素。(3)從貧營養(yǎng)土樣中分離出5株貧營養(yǎng)微生物,分別編號為P1、P2、P3、P4和P5,經(jīng)鑒定,P1、P2、P3和P5屬鏈霉菌屬,P4菌為枯草芽孢桿菌。P4菌的最適生長溫度為37℃,最適pH值在7-8之間,培養(yǎng)基最適含碳量為15 mg/L。(4)P4菌具有很強的溶磷和解鉀作用,其生長可以有效改善貧營養(yǎng)土壤肥力,為其他土壤微生物和植物生長提供營養(yǎng)物質�；哪寥绹姙4菌劑后,土壤的含水量和持水性顯著提高,滲水性顯著下降,有利于表層土壤水分的保持。
[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，

本文編號：2248920