川西高山森林倒木不同分解阶段的微生物群落变化特征  

The dynamics of microbial community structure at different stages of log decay in an alpine forest of western Sichuan

作　　者：常晨晖 吴福忠[1] 杨万勤[1] 谭波[1] 李晗[1] 肖洒[1] 苟小林[1] 何丽娜[1] 

机构地区：[1]四川农业大学生态林业研究所长江上游林业生态工程重点实验室,成都611130

出　　处：《应用与环境生物学报》2014年第6期978-985,共8页Chinese Journal of Applied and Environmental Biology

基　　金：国家自然科学基金项目(31170423;31270498);国家"十二五"科技支撑计划项目(2 011BAC09B05);四川省杰出青年学术与技术带头人培育项目(2012JQ0008;2012JQ0059);中国博士后科学基金项目(2012T50782)资助~~

摘　　要：微生物是倒木分解的积极参与者,而不同分解阶段的倒木也为微生物群落提供了重要的生长基质,可能形成差异显著的微生物群落结构.为了解高山森林倒木分解过程中微生物群落演变特征,采用磷酸脂肪酸(PLFA)分析技术研究一个分解序列的川西高山森林岷江冷杉(Abies faxoniana)倒木心材、边材和树皮微生物生物量及群落结构特征.结果表明,随着腐烂等级增加,微生物总生物量、真菌生物量和细菌生物量均表现出相对一致的变化规律,但不同结构组分微生物生物量随腐烂等级增加的变化特征具有一定的差异.其中,心材微生物生物量在Ⅰ-Ⅳ随腐烂等级的增加缓慢升高,但在Ⅴ腐烂等级快速增加;边材和树皮在Ⅱ和Ⅲ腐烂等级微生物生物量最低;除Ⅲ腐烂等级树皮,整个分解序列的倒木真菌/细菌比值在0.22-0.73之间,随腐烂等级增加而降低.PLFA单体尤其是优势脂肪酸单体含量变化显著(P<0.05)影响微生物群落多样性指数,且与倒木不同结构组分在各分解阶段的理化特征密切相关.此外,聚类分析表明Ⅲ、Ⅳ、Ⅴ腐烂等级心材,Ⅲ、Ⅳ、Ⅴ腐烂等级边材,Ⅰ-Ⅴ腐烂等级树皮微生物群落结构相似度较高;Ⅰ、Ⅱ腐烂等级心材与Ⅰ、Ⅱ腐烂等级边材微生物群落结构具有较高的相似度.可见,高度腐烂的倒木表现出相对较高的微生物生物量及丰富的群落类群,但不同结构组分在腐解过程中微生物群落结构特征具有相对独立的变化趋势,这对深入了解高山森林倒木分解与微生物群落演替的相互关系具有重要意义.Microorganisms play an active role during the log decay process in forest ecosystems. Logs of different decay stages can provide various kinds of substrate for the growth and reproduction of microorganisms, changing the structure of microbial community. This research was to determine the dynamics of microbial community structure and biomass in heartwood, sapwood and bark at different log decay stages using phospholipid fatty acid （PLFA） profiling method. The fallen fir （Abies faxioniana） logs at different decay stages were randomly selected from an alpine forest in western Sichuan, China. The results indicated a significant increase tendency in total PLFAs （microbial biomass）, bacterial and fungal PLFAs with the increase of decay stages, in comparison with the low microbial biomass in sapwood and bark observed at the II and III decay stages, microbial biomass in heartwood increased with the decay stage. The fungal to bacteria ratio was 0.22-0.73 and decreased with the decay stage, implying that bacteria could dominate the log decay process. A total of 42 kinds of PLFA were detected, with dominant PLFAs significantly influencing the diversity index. PLFA 18：2ω6,9c and 18：1ω9t were related with the degradation of cellulose and lignin, and aerobic bacteria 16：1ω7c showed much higher contents in heartwood and sapwood at advanced decay stages. Principal component analysis （PCA） showed microbial community significantly different at different decay stages, especially between I and V decay stages. Cluster analysis found high similarity in microbial community structure among heartwood of decay stages III - V, sapwood of stages III - V, and bark of stages I - V. It also showed high similarity of microbial community structure between heartwood of decay stages I and II, and sapwood of stages I and II. These results provide efficient scientific evidences for understanding the relationships between log decay and microbial community dynamics in alpine forests.

关 键 词：川西高山森林 倒木分解 磷酸脂肪酸 腐烂等级 微生物群落演替 岷江冷杉 

分 类 号：S718.8[农业科学—林学]