喀斯特生态系统中乔木和灌木林根际土壤微生物生物量及其多样性的比较  

Comparison of Microbial Biomass and Community Structure of Rhizosphere Soil Between Forest and Shrubbery in Karst Ecosystems

作　　者：王新洲[1] 胡忠良[1] 杜有新[1] 刘永卓[1] 李恋卿[1] 潘根兴[1] 

机构地区：[1]南京农业大学农业资源与生态环境研究所,南京210095

出　　处：《土壤》2010年第2期224-229,共6页Soils

基　　金："973"国家重点基础研究发展计划项目(2006CB403200)资助

摘　　要：我国喀斯特区域面积分布较广,而喀斯特生态系统的退化已成为当前西南地区面临的严重的生态问题。本研究选取贵州中部两种不同植被类型的生态系统—乔木林和灌木林,以乔木林中的白栎、园果化香和灌木林中的火棘、竹叶椒等主要优势树种为对象,研究不同的植物树种对根际土壤微生物生物量及其细菌群落结构的影响。结果显示:乔木林系统中根际土壤微生物生物量碳、氮显著性高于灌木林,植物的根际效应在乔木林中表现更为显著;同时乔木林中的优势树种通过根系分泌物的作用显著提高根际土壤细菌多样性指数,而灌木林中优势树种的根际土壤微生物量及多样性均未表现出明显的根际效应。因此,植被的演替通过改变土壤微生物的特性影响植物-微生物-土壤之间的物质和能量循环,进一步影响喀斯特生态系统的稳定和健康功能。The degradation of karst ecosystem in Southwest China has been a serious ecological problem. To research the effects of different vegetation types on microbial hiomass and bacterial community structures of rhizosphere soil, we selected the dominant tree species, Quercusfabri, Platycarya longipes in forest and Pyracanthafortuneana, Zanthoxylumplanispinum in shrubbery, in two typical karst ecosystems. The results showed that microbial biomass carbon and nitrogen of rhizosphere soil in forest were higher than those in shrubbery, and the effects of the dominant tree species of Quercusfabri and Platycarya longipes in forest was more obvious compared to shrubbery. Bacterial diversity indexes of rhizosphere soil of dominant tree species in forest were significantly higher than those of bulk soil by the root exudates, but in shrubbery, there was no significant diffcrenoe in both microbial biomass and diversity indexes between rhizosphere soil and bulk soil. It suggests that the vegetation succession could affect the cycle of substance and energy among plant-microbe-soil system by changing the characters of soil microbe, even affect the stabilization and health ofkarst ecosystems.

关 键 词：喀斯特生态系统 根际土壤 微生物生物量 细菌群落 DGGE 

分 类 号：S154.3[农业科学—土壤学]