荒漠草原中间锦鸡儿灌丛的土壤微生物多样性

Soil microbial community diversity of Caragana intermedia shrubs in the desert steppe

为了探究内蒙古荒漠草原中间锦鸡儿灌丛对土壤微生物群落的影响,采用传统培养法和分子生物学技术,比较中间锦鸡儿灌丛内外细菌、真菌和放线菌群的种群差异,并且分析土壤微生物群落与环境因子的关系.结果发现:中间锦鸡儿灌丛土壤微生物总数表现为细菌>放线菌>真菌;土壤微生物的数量和Shannon-Weiner指数均在表层土或次表层土中最大.这说明中间锦鸡儿灌丛土壤微生物具有明显的垂直分布异质性.灌丛内土壤微生物的数量和多样性均大于灌丛外的数值,Lysobacter、诺卡氏菌属只集中在灌丛内,这说明中间锦鸡儿灌丛能够影响土壤微生物的组成和多样性.冗余分析结果表明,土壤环境对中间锦鸡儿灌丛土壤细菌和真菌的影响较大,对放线菌没有显著影响,速效钾和硝态氮是影响土壤细菌和真菌的主要环境因素.

To explore the influence of Caragana intermedia shrubs on the soil microbial communities in the desert steppe in Inner Mongolia Plateau,traditional culture methods and molecular biological techniques were combined to compare the dif-ference of soil microorganisms,including bacteria,fungi and actinomycete,inside and outside shrubs canopies of Caragana intermedia. Furthermore,the relationships of soil microbial communities and environmental factors were analyzed. The re-sults showed that the quantity of soil microorganisms of Caragana intermedia shrubs followed the pattern,i.e. bacteria actino-mycetes fungi,and the quantity and Shannon-Weiner index of bacteria,fungi,actinomycetes were the highest at the surface or subsurface soil. This suggested that there was significant vertical distribution heterogeneity for soil microor-ganisms of Caragana intermedia shrubs. The quantity and diversity of soil microorganisms inside the shrubs were higher than those outside the shrubs. Lysobacter and Nocardia were only observed inside the shrubs,which suggested that Caragana intermedia shrubs had significant influence on the composition and diversity of soil microorganisms. The results of RDA analy-sis showed that the soil environment had greater influence on the bacterial and fungi communities,and had no significant influence on the actinomycete community. Among the environmental factors,soil available potassium and nitrate nitrogen were the most important factors which can influence the bacterial and fungi communities.