高寒地区不同退化草地植被特性和土壤固氮菌群特性及其相关性

发布时间：2018-02-01 04:01

本文关键词： 高寒草地草地退化植被特性固氮菌 nifH基因　出处：《生态学报》2017年11期 　论文类型：期刊论文

【摘要】：选取东祁连山不同退化程度的高寒草地为研究对象,调查研究其植物种类、植被盖度、高度、地上生物量等植物指标以及土壤好气性自生固氮菌和嫌气性自生固氮菌数量,在此基础上,采用real-time PCR的方法扩增nifH基因,测定不同退化程度草地土壤中固氮菌相对于土壤总细菌的量,以探讨草地退化过程中植被及土壤固氮菌群的变化规律,结果发现:随着退化程度的加深,草地植物种类逐渐减少,并且优势植物发生变化,毒杂草逐渐增多,植被的高度、盖度、地上生物量都逐渐降低。对土壤固氮菌的研究则表明,土壤好气性自生固氮菌和嫌气性自生固氮菌的数量在不同退化草地随草地退化程度的加重而减少,在同一退化程度草地土壤则是随土层深度加深而下降。对土壤固氮菌nifH基因扩增的结果也表明随着退化加剧,土壤固氮菌相对于土壤总细菌的比例在降低,进一步说明草地退化过程中土壤固氮菌不仅是数量上的下降,更是群落结构层面的变化。对植被特性和土壤固氮菌含量的相关分析表明,植被特性和土壤中固氮菌含量呈显著相关。研究从土壤固氮菌群的角度研究了草地退化的过程,说明了二者具有协同性,研究和治理草地退化必须重视土壤功能菌群尤其是固氮菌群的作用。
[Abstract]:The alpine grassland with different degrees of degradation in the eastern Qilian Mountains was selected as the research object, and the plant species, vegetation coverage and height were investigated and studied. On the basis of plant indexes such as aboveground biomass and the number of aerobic autogenous nitrogen-fixing bacteria and aerobic autogenous nitrogen-fixing bacteria in soil, the nifH gene was amplified by real-time PCR. The amount of nitrogen-fixing bacteria relative to soil total bacteria in grassland with different degradation degree was measured in order to study the change law of vegetation and soil nitrogen-fixing bacteria in the process of grassland degradation. The results showed that: with the deepening of degradation degree. The species of grassland plants gradually decreased, and the dominant plants changed, toxic weeds gradually increased, vegetation height, coverage, aboveground biomass gradually decreased. The study on soil nitrogen-fixing bacteria showed that. The number of aerobic autogenous nitrogen-fixing bacteria and actinomycetes in different degraded grassland decreased with the increase of grassland degradation degree. The results of nifH gene amplification of soil nitrogen-fixing bacteria also showed that the degradation increased with the degradation of grassland soils with the same degree of degradation. The ratio of soil nitrogen-fixing bacteria to soil total bacteria is decreasing, which further indicates that soil nitrogen-fixing bacteria are not only decreasing in quantity during grassland degradation. The correlation analysis of vegetation characteristics and soil nitrogen-fixing bacteria content showed that. There was a significant correlation between vegetation characteristics and soil nitrogen-fixing bacteria content. The process of grassland degradation was studied from the point of view of soil nitrogen-fixing bacteria community. To study and control grassland degradation, we must attach importance to the function of soil microbial community, especially nitrogen fixing bacteria.
【作者单位】：甘肃农业大学草业学院;草业生态系统教育部重点实验室;深圳市芭田生态工程股份有限公司博士后研究中心;
【基金】：国家自然科学基金项目(31360584) 农业部国家牧草产业技术体系(CARS-35)
【分类号】：S812
【正文快照】： 草地生态系统是陆地上最重要的生态系统,具有防风、固沙、保土、调节气候、净化空气和涵养水源等生态功能,对于地球生物圈的稳定与平衡和人类社会可持续发展具有重要意义。我国是世界第二大草原国家,草地资源在国土资源中占据相当重要的地位,具有极其重要的生态价值、经济价值

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