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梵净山典型植被类型的根系真菌群落结构及功能类群特征研究

Community Structure of Root-associated Fungi and Functional Characteristics in Typical Vegetation Types of Fanjingshan

  • 摘要:
    目的 解析世界自然遗产地梵净山地区典型植被类型对真菌群落结构及功能的影响,为深入探讨可见的地上植物群落和未知的地下真菌群落结构间的关联机制提供数据支撑。
    方法 以梵净山常绿阔叶林、常绿落叶阔叶混交林和亚高山矮林3种植被类型为研究对象,高通量测序技术探讨根系真菌群落结构在植被类型间的差异,FUNGuild对真菌进行功能预测,并分析真菌群落与土壤性质、细根性状和叶性状间的关系。
    结果 子囊菌门和担子菌门为优势真菌门,undefined saprotroph、丛枝菌根真菌、外生菌根真菌、植物病原菌、内生真菌、寄生性真菌和杜鹃花类菌根真菌为主要功能类群。常绿阔叶林、常绿落叶阔叶混交林和亚高山矮林的显著差异功能类群分别是丛枝菌根真菌、外生菌根真菌和杜鹃花类菌根真菌。真菌群落组成在植被类型间存在显著差异,常绿阔叶林真菌多样性和Shannon指数显著高于常绿落叶阔叶混交林和亚高山矮林,而Bray-Curtis相异性指数在亚高山矮林显著低于常绿阔叶林和常绿落叶阔叶混交林。ABT分析表明,根碳含量是影响真菌丰富度的首要因子,叶干物质含量是影响真菌Shannon指数、Simpson指数和Pielou指数的首要因子。冗余分析揭示植被类型、土壤pH、根碳含量和叶碳含量显著影响真菌群落;方差分解分析表明植被类型对真菌群落的影响最大,其次是细根性状和土壤性质,叶性状影响最小。差分解分析表明植被类型对真菌群落的影响最大,其次是细根性状和土壤性质,叶性状影响最小。
    结论 植被类型能显著影响真菌群落结构,真菌功能类群与植被类型间存在某种特定联系,植物性状对根系真菌群落的构建具有重要意义。

     

    Abstract:
    Objective To reveal the effects of vegetation types on root-associated fungal community structure and function in the Fanjingshan World Heritage property, supportive data was provided to predict the relationships between visible vegetation types and invisible community structure in terrestrial ecosystem.
    Method Three representative vegetation types, including an evergreen broadleaved forest (EBF), an evergreen and deciduous broad-leaved mixed forest (EDBMF) and a subalpine dwarf shrub (SDF), were investigated in the Fanjingshan. Illumina MiSeq sequencing and the FUNGuild annotation tool were used to obtain and analyse the characteristics of the root-associated fungal community structure and function in different vegetation types, and the contributions of soil properties, fine root traits and leaf traits to variations in composition of root-associated fungal community were also analysed.
    Result Ascomycota and Basidiomycota were the two most abundant phyla, and undefined saprotroph, arbuscular mycorrhizal fungi, ectomycorrhizal fungi, plant pathogen, endophyte, fungal parasite and ericoid mycorrhizal fungi were the main guilds. Arbuscular mycorrhizal fungi were notably enriched in EBF, ectomycorrhizal fungi were more significantly abundant in EDBMF, and ericoid mycorrhizal fungi were significantly overrepresented in SDF. The significant difference in the composition of root-associated fungi among vegetation types was confirmed by non-metric multidimensional scaling analysis and permutational multivariate analysis of variance. A higher alpha diversity was detected in EBF, and the Bray-Curtis dissimilarity index was significantly lower in SDF than in EBF and EDBMF. Aggregated boosted tree analysis indicated that root carbon content was the primary factor influencing observed richness, while leaf dry matter content was the dominant factors associated with the changes in Shannon index, Simpson index and Pielou index of root-associated fungi. Redundancy analysis showed that changes in vegetation type, soil pH, root carbon content and leaf carbon content could significantly affect the fungal community composition. The variance partitioning analysis further revealed that vegetation type had the greatest impact on the composition of root-associated fungi, followed by fine root traits and soil properties, and leaf traits had the least impact.
    Conclusion Vegetation type can significantly affect root-associated fungal community structure. There is a specific relationship between vegetation type and functional taxa, and plant traits affect the construction of fungal communities.

     

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