菌根类型对不同树种吸收根混合分解的影响机制

凋落物分解已经成为生态系统仅次于初级生产力的主要功能，混合分解作为分解的特有形式，对碳循环具有更实际意义。尽管大尺度物种多样性与叶片混合分解已取得长足进展，而关于树种多样性与地下吸收根混合分解的研究还非常匮乏。此外，菌根类型是影响根属性和过程的重要因素，但多树种共生，其菌根类型对吸收根混合分解的调控作用鲜有报道。本项目拟结合野外原位取样与室内培养等方法，研究我国亚热带森林不同菌根(内生和外生)乔木树种吸收根混合分解规律。重点研究：1）菌根类型对不同树种吸收根混合分解的时间变异规律及调控作用；2）基于调控不同菌根树种吸收根分解的特定化学属性及其直径数据，探讨菌根类型对不同直径大小树种吸收根混合分解的影响。研究结果将为更好地理解菌根类型在整个吸收根混合分解过程中的调控作用，明晰不同菌根类型吸收根特定化学属性对其混合分解的影响机制，为森林经营管理中树种合理配置及固碳能力提升提供科学依据。

Litter decomposition has become the main function that next to primary productivity in ecosystems, and litter mixture decomposition as the special form has more practical significance for the carbon cycling. Although the relationships between leaf mixture decomposition and biodiversity have made great progress at large scale, the research on species diversity and absorptive root mixture decomposition is still scarce. Furthermore, although mycorrhizal types are the key factor influencing root traits and processes, the effects on absorptive root mixture decomposition of different mycorrhizal co-growth species are rarely considered. By combining field sampling with a microcosm decomposition experiment, this project attempts to explore the absorptive root mixture decomposition of woody tree species associated with contrasting mycorrhizal (arbuscular mycorrhizal vs. ectomycorrhizal) fungi in subtropical forests in China. The main objectives aim at examining: 1) temporal variation and influence of mycorrhizal types on the mixed decomposition of absorptive root of different tree species; 2) based on the specific chemical traits and diameter of absorptive root decomposition of different mycorrhizal tree species, the effects of mycorrhizal types on mixed absorptive root decomposition of different diameter tree species. This study will provide evidence for better understanding the role of mycorrhizas in the whole process of mixed absorptive root decomposition and illustrating the underlying mechanism of specific chemical traits on the mixed absorptive root decomposition, and also provide a scientific basis for the rational allocation of tree species and the improvement of carbon sequestration capacity in forest management.