毛竹扩张中土壤微生物群落演替与叶片可分解性、次生代谢产物的耦合机制

It has raised significant concern that widespread expansion of moso bamboo (Phyllostachys edulis) causes degradation of adjacent forest ecosystem and change of landscape. Current studies on effects of moso bamboo expansion have mostely focused on the vegetation diversity and soil nutrient cycling processes change, while the coupling between soil microbial community and plant functional traits far less studied. In the present project, the concept of “aboveground and belowground biotic linkages” will be introduced and next generation high-trough sequencing technique as well as traditional ecological research methods will be applied. This project intends to investigate the successional dynamics of soil microbial communities, leaf decomposability, nutrients return and polyphenols secondary metabolite during moso bamboo expansion, and to determine the correlative relationship between soil microbial community and plant functional traits, hoping to reveal the underling ecological mechanism of moso bamboo expansion by linking aboveground and belowground. Results from this project will guide the management measures for controlling moso bamboo expansion, and also provide theoretic and technique support for guiding forest restoration practices.

毛竹大范围扩张引起相邻森林生态系统功能退化与景观变化已成为生态学的重要问题。目前有关毛竹扩张机制的研究大多关注地上植被群落多样性和土壤养分循环过程的变化，而对土壤微生物群落演替与植物叶片功能属性变异的耦合机制关注极少。本项目引入“地上-地下生物学联系”这一概念，以毛竹扩张样带为研究对象，在毛竹纯林、竹-阔(针)混交林和阔(针)叶林的连续样带中，将高通量测序技术和传统生态学研究方法相结合，研究土壤微生物群落、叶片可分解性、养分归还状况及多酚类次生代谢产物等指标的演变规律，阐明土壤微生物群落演替与叶片可分解性、多酚类次生代谢产物的耦合关系。研究结果拟从生态系统地上-地下生物学联系角度阐明毛竹扩张机制，并为合理调控毛竹林扩张过程提供科学依据，为森林恢复实践提供理论指导。

毛竹大范围扩张对相邻生态系统功能退化与景观变化已成为生态学的重要问题。然而，毛竹扩张过程中土壤微生物群落演替与叶片可分解性、植物次生代谢产物的耦合机制还不十分清楚。因此，本项目选择江西省井冈山国家级自然保护区毛竹扩张样带为研究对象，采用野外调查和室内分析相结合的方法，研究了1)毛竹扩张过程中土壤微生物群落结构和功能的演替规律；2）毛竹扩张过程中植物叶片可分解性和养分归还的动态变化；3）毛竹扩张过程中植物多酚次生代谢产物的动态变化。结果表明：1）毛竹向阔叶林扩张和向针叶林扩张均降低了真菌与细菌的比值，表明毛竹可能通过构建细菌占优势的食物网形成，从而实现种群的扩张；2）毛竹向阔叶林扩张和向针叶林扩张均显著增加凋落物分解速率，但降低土壤总磷的归还，表明毛竹可能通过增加土壤养分的归还，满足自身快速生长对养分的需求，同时增加土壤P对相邻生态系统植被生长的限制，实现种群的扩张；3）毛竹向阔叶林扩张增加叶片纤维素和木质素含量，毛竹向针叶林扩张增加叶片木质素含量，表明毛竹可能通过分配更多的碳到叶片中增加叶片的寿命，从而获得竞争优势，实现种群的扩张。总之，毛竹通过叶片次生代谢产物、叶片可分解性及土壤微生物群落的联级效应，实现种群的扩张。该结果对于合理调控毛竹林扩张过程提供科学依据。