四川九龙山自然保护区林麝栖息地典型植被土壤微生物群落特征

Microbial Community Characteristics of Typical Vegetation Soil at Forest Musk Deer Habitats in Sichuan Jiulong Mountain Nature Reserve

为了解四川九龙山自然保护区林麝栖息地典型植被(灌木林、针阔混交林和阔叶混交林)下土壤微生物群落特征,探讨土壤微生物类群对地表植被组成的影响。采用平板稀释法进行活菌计数与菌株分离,16SrRNA PCR鉴定分离菌,常规方法测定土壤理化学性质。结果表明,栖息地各植被类型下共由11种细菌菌属组成;以芽孢菌占主要部分,韦氏芽胞杆菌(Bacillus weihenstephanensis)、巨大芽胞杆菌(Bacillus megaterium)和苏云金芽胞杆菌(Bacillus thuringiensis)为优势菌群。各植被类型土壤均以细菌为主,放线菌次之,真菌最少;土壤微生物总数排序为灌木林>针阔混交林>阔叶混交林;各植被类型下不同土层中微生物的分布趋势是0~20cm>20~40cm>40~60cm。相关性分析结果表明,pH值与放线菌呈显著正相关性(R=0.676,P<0.05),总微生物与细菌总数呈极显著正相关性(R=1,P<0.01),总微生物与放线菌呈显著正相关性(R=1,P<0.01)。

The objectives of this study were to explore the characteristics of soil microbial communities in the soils of typical vegetations （shrub forest, mixed coniferous and broad-leaved mixed forest） at forest musk deer habitat in Sichuan Jiulong Mountain Nature Reserve,and to examine the effects of soil microbi- als on the composition of ground vegetations. The number of soil colonies was determined by plate colony dilution method. Isolated soil bacteria and actinomycetes were identified by 16S rRNA PCR method. Soil physicochemical properties were determined by the conventional methods. Eleven species of microorganisms were identified. They were mainly consisted of Bacillus weihenstephanensis, B. rnegaterium and B. thuringiensis. Among the microorganisms isolated from the soil of three vegetation types, the number of bacteria （over 70%） represented absolute advantage,actinomycetes were followed,and no fungi were sepa- rated. Distribution trend in three soil types of microorganisms in the soil profile was 0-20〉20-40〉40- 60 cm. The correlation analysis indicated that pH value was significantly and positively correlated to actino-mycetes （R=0. 676,P〈0.05）. Total microorganisms were signi{icantly and positively correlated to total bacteria （R=1,P〈0.01）. The correlationship between total microorganismsl and actinomycetes was sig- nificant and positive （R=1,P〈0.05）.