长白山岳桦外生菌根真菌多样性: 分布格局, 构建过程和生态功能

Ectomycorrhizal fungi (EcMF) is one functional guild among soil biota, which is mutualistic with terrestrial plant roots. Meanwhile, EcMF is a key component of forest belowground biodiversity, which determines the health, stability and succession of forests. Currently, EcMF diversities of different plants on different localities have been largely studied, however, the comprehensive studies on the vertical distribution pattern, community assembly process and ecosystem functioning of EcMF diversity of single plant host in high and cold environment are very lack. Changbai Mountains have the biggest vertical belt of Erman’s birch forest in eastern Asia, which reflect the miniature of horizontal distribution pattern of single plant species. As such, the Erman’s birch forest in Changbai Mountains is a wonderful natural platform to study EcMF diversity. This project plans to collect fine roots and adjacent soil of Butula ermanii at different transects and different elevational habitats, including north, west and south slopes. By integrating field investigation, high-throughput sequencing and the measurement of soil properties, extracellular enzyme activities and plant nutrients, we will build the distribution modelling of EcMF diversity of B. ermanii, clarify the assembly process of EcMF communities, and reveal the potential coupling between EcMF diversity and functioning (viz. enzyme activities and plant, soil nutrient content). The results will strengthen our comprehensive understanding on the pattern, process and functioning of EcMF diversity in high-cold environment, and provide scientific references for raising mycorrhizal seedlings and vegetation restoration in the upper area of Changbai Mountains.

外生菌根真菌(EcMF)是一类与陆地植物根系互惠共生的土壤功能类群，是森林地下生物多样性的关键组分，决定了森林的健康、稳定与发展。目前，不同地点不同植物EcMF的多样性已有大量研究，然而高寒环境中单种植物EcMF多样性的垂直分布规律、群落构建过程及其生态系统功能的综合研究还很缺乏。长白山保有东亚地区最为完整的岳桦垂直分布带，反映和浓缩了单种植物水平地带性分布的特点，是研究EcMF多样性的天然实验场。本项目拟采集长白山北-西-南三个坡向不同海拔生境的岳桦细根和根围土壤，结合野外调查、高通量测序、土壤属性、胞外酶及植物养分元素测定等手段建立岳桦EcMF多样性的分布模型，阐明EcMF群落的构建过程，并揭示EcMF多样性和功能（胞外酶活性和植物、土壤养分含量）的关联。研究结果将加深我们对高寒环境EcMF多样性格局、过程和功能的综合认知，为岳桦菌根化育苗及长白山上界困难立地植被恢复工作提供科学依据。

外生菌根真菌(EcMF)是一类与陆地植物根系互惠共生的土壤功能类群，是森林地下生物多样性的关键组分，决定了森林的健康、稳定与发展。目前，不同地点不同植物的EcMF多样性已有大量研究报道，然而高寒环境中单种植物EcMF多样性的垂直分布规律、群落构建过程及其生态系统功能的综合研究还很缺乏。长白山保有东亚地区最为完整的岳桦垂直分布带，反映和浓缩了单种植物水平地带性分布的特点，是研究EcMF多样性的天然实验场。本项目采集了长白山不同海拔生境的岳桦细根和根围土壤样品共计168份，结合野外调查、高通量测序、土壤属性、植物细根养分特性以及植物单核苷酸多态性（SNPs）测定等手段，1）建立了岳桦EcMF多样性的分布模型：提出了岛屿生物地理学理论中的各要素（岛屿的面积、隔离程度和能量）以及生物互作效应（即腐生真菌多样性）共同决定了EcMF多样性在细根和根围土壤生境中的分布模式；2）阐明了岳桦EcMF群落的构建过程：发现植物种间系统发育关系显著地驱动了细根EcMF群落组成，地理距离则主要影响了腐生真菌的群落组成。此外，确定性过程和随机性过程分别主导了岳桦EcMF和腐生真菌的群落构建方式；3）揭示了真菌（包括EcMF和腐生真菌）对高寒林线生态系统中多界生物群落的稳定与连接作用：真菌的存在加固了多界网络拓扑结构的稳定性，并在群落水平架起了连通地上和地下生物区系的桥梁。上述研究结果加深了我们对高寒环境EcMF多样性格局、过程和功能的综合认知，为岳桦菌根化育苗以及长白山上界困难立地植被恢复工作提供了科学参考。