模拟根系分泌物碳输入对凋落叶分解中微生物群落动态的影响  

Effects of simulated root exudate carbon inputs on the dynamics of microbial communities during litter decomposition

作　　者：胡凯 陶建平 黄科 胡靖 王微 HU Kai;TAO Jianping;HUANG Ke;HU Jing;WANG Wei(College of Forestry and Life Science,Institute of Microbial Ecology,Chongqing University of Arts and Sciences,Chongqing 402168,China;Key Laboratory of Eco-environments of Three Gorges Reservoir Region(Ministry of Education),Chongqing Key Laboratory of Plant Ecology and Resources of Three Gorges Reservoir Region,School of Life Science,Southwest University,Chongqing 400715,China)

机构地区：[1]重庆文理学院林学与生命科学学院,微生物生态学研究所,重庆402168 [2]西南大学生命科学学院,三峡库区生态环境教育部重点实验室,重庆市三峡库区植物生态与资源重点实验室,重庆400715

出　　处：《应用与环境生物学报》2020年第2期417-424,共8页Chinese Journal of Applied and Environmental Biology

基　　金：国家自然科学基金项目(31700539);重庆市基础科学与前沿技术研究专项项目(cstc2017jcyjAX0289)资助。

摘　　要：为深入理解根系分泌物对森林凋落物分解的影响,通过20 d的室内培养实验,在土壤中添加4种不同浓度的人工模拟根系分泌物中活性有机碳复合物(每克土壤添加0、0.3、0.6和1.2 mg碳),研究活性有机碳输入对凋落叶分解和微生物群落的影响.结果显示,一定浓度模拟根系分泌物碳输入(每克土壤添加0.6、1.2 mg碳)可引起凋落叶表面微生物数量特别是真菌数量的相对增加,并且明显改变凋落叶分解过程中微生物群落的种类组成,激活一些快速生长的真菌,促进微生物代谢活力,使分解率提高了19.0%-26.2%.根系分泌物碳添加、取样时间及其二者的交互作用均对凋落叶表面β-葡萄糖苷酶和β-N-乙酰葡糖氨糖苷酶的活性产生显著影响,随着分解时间的推进,0.6 mg和1.2 mg碳添加处理能显著提高这两种酶的活性.根系分泌物碳添加对凋落叶表面古菌硝化功能基因amoA和细菌硝化功能基因amoA的数量均无显著影响,但在分解20 d取样,0.6 mg碳添加处理能明显提高固氮功能基因nifH和反硝化功能基因nosZ的数量.本研究表明一定浓度根系分泌物输入能够改变微生物群落组成与数量,并提高微生物胞外酶活性,加速凋落物分解,且激发效应的启动由底物添加的碳含量和活跃的微生物群落相互作用决定.(图5表4参36)To understand how root exudates influence litter decomposition in forest ecosystems,a simulation experiment using four different C concentrations(0,0.3,0.6,and 1.2 mg C/g soil)was performed.C-containing compounds often found in root exudates were added to soils to assess how labile C inputs regulate litter decomposition and soil microbial communities of litter surface in a 20-d laboratory incubation.The results indicated that a certain concentration of root exudate C inputs(0.6 and 1.2 mg C/g soil)caused a relative increase in the number of microbes,especially fungi,on the surface of leaf litter,which obviously changed the composition of microbial communities during the process of litter decomposition,which was activated by some fast-growing fungi,and promoted microbial metabolic activities,which led to an increase in the decomposition rate of 19.0%-26.2%.Root exudate C addition,sampling time,and their interaction had significant effects on the activity ofβ-glucosidase andβ-N-acetylglucosaminidase on the litter surface.With prolonged decomposition,both 0.6 and 1.2 mg C/g soil addition can significantly increase the activities of these two enzymes.Root exudate C addition had no significant effect on the number of archaeal amoA or bacterial amoA on the surface of the litter.However,the treatment of 0.6 mg C/g soil addition significantly increased the copy number of the nifH and nosZ genes on the 20th day of decomposition.In summary,a certain concentration of root exudates may change the composition and quantity of microbial communities,increase the extracellular enzyme activities of microbes,and thus accelerate litter decomposition.In addition,the initiation of the priming effect was determined by the interaction of the C content added by the substrate and the active microbial communities.

关 键 词：根系分泌物 凋落叶 分解 微生物群落 微生物数量 酶活性 

分 类 号：S714[农业科学—林学]