三峡库区马尾松林土壤真菌群落特征及影响因素

Characteristic of soil fungal community and the influencing factors of Pinus massoniana forests in the Three Gorges Reservoir Region

土壤真菌是地下生物多样性的重要组成部分,在土壤碳和养分循环中发挥重要功能。本研究基于高通量测序技术对三峡库区22个马尾松林表层土壤(0~10 cm)真菌群落进行研究。结果表明:子囊菌门与担子菌门为优势真菌类群,常见类群包括散囊菌目、红菇目和银耳目。真菌功能群以腐生真菌与外生菌根真菌为主,欧石南类菌根真菌也较常见。冗余分析表明,无论是对整个土壤真菌群落还是不同真菌功能群,环境变量对群落结构的影响均强于空间变量,说明在较小的空间尺度上生境过滤对土壤真菌群落结构的影响超过扩散限制。地上生物量、电导率、有效磷、容重、碳氮比、硝态氮、粉粒占比是影响真菌群落结构的主要环境因子,但影响不同真菌功能群的最关键环境因子存在差异。

Soil fungi are important components of belowground biodiversity and play important roles in soil carbon and nutrient cycling.We investigated fungal communities in the top soil(0-10 cm)of 22 Pinus massoniana forests in the Three Gorges Reservoir Region using high-throughput sequencing technique.We found that Ascomycota and Basidiomycota were the dominant fungi phyla,and Eurotiales,Russulales,and Tremellales were the most abundant fungi orders.The dominant functional groups in P.massoniana forests were saprophytic fungi,ectomycorrhizal fungi,and ericoid mycorrhizal fungi.Results of redundancy analysis showed that environmental variables but not spatial variables were the main drivers of soil fungal community structure across the 22 P.massoniana forests,which suggested that habitat filtering rather than dispersal limitation shaped soil fungal community structure.Aboveground biomass,soil conductivity,available phosphorus,soil bulk density,carbon to nitrogen ratio,nitrate concentration,and proportion of slit were the main factors explaining the variation in soil fungal community structure.It should be noted that the key factors influencing different fungal functional groups differed across forests.