【摘要】 目的】为揭示森林树木组成和生物量优势与土壤养分和肥力之间的关系。【方法】以江西九连山国家级自然保护区的典型亚热带森林为研究对象，随机设置116个20 m×20 m样方并调查样方内树木（胸径≥5 cm）信息。根据全球植物菌根数据库确认每种树木菌根类型，分为丛枝菌根（AM）和外生菌根（ECM）树。利用基础信息和生物量方程计算AM和ECM树的多样性指数，包括Simpson指数（优势度）、Pielou指数（均匀度）和Margalef指数（丰富度），以及每棵树木地上生物量，同时计算出每块样方内AM树种和ECM树种分别与该样方内总地上生物量的比值作为生物量优势值(R_AM/总、R_ECM/总)，以此来表征2种类型菌根树种在生物量上的相对大小关系。采集0～20 cm表层土壤并测定土壤有机质（SOM）、全氮（TN）、全磷（TP）及速效养分含量，并以土壤养分提取的第一主成分评估土壤肥力。【结果】菌根真菌对其共生树种的丰富度和优势度均有显著影响，且AM树种的Simpson指数和Margalef指数显著高于ECM树种；2类树种的多样性指数与生物量优势对土壤氮磷含量的影响不同，其中AM树种的Margalef指数和Pielou指数分别与TP和AP含量呈显著正相关，而ECM树种的Margalef指数和Pielou指数与TP和AP含量之间无显著相关，R_AM/总与土壤NO₃^--N和AP含量之间存在显著正相关关系。就土壤肥力而言，2种类型树种的多样性指数越高，土壤肥力越大，但R_AM/总与土壤肥力间并无显著相关关系。【结论】在亚热带森林中，菌根树木多样性和生物量优势均对土壤养分产生影响，且菌根是通过改变共生树种地上生物量而非菌根树种多样性来影响该过程；尽管菌根树木多样性能够影响土壤肥力，但菌根树木多样性并未对该过程产生显著影响。更多还原

【Abstract】 [Objective]The primary objective of this research is to investigate the intricate relationship between forest tree composition,biomass dominance,and the availability and fertility of soil nutrients.[Method]The study was conducted in a typical subtropical forest situated within the Jiulianshan National Nature Reserve in Jiangxi Province,China.We established 116 randomly located plots,each measuring 20 m×20 m,to conduct a detailed survey of tree species,focusing on individuals with a diameter at breast height（DBH） of 5 cm or more.The mycorrhizal type of each tree species was determined based on the Global Plant Mycorrhizal Database,categorized into arbuscular mycorrhizal （AM） and ectomycorrhizal （ECM） trees.The diversity indices of AM and ECM trees,including the Simpson index （dominance）,Pielou index （evenness）,and Margalef index （richness）,as well as the above-ground biomass of each tree,were calculated using basic information and biomass equations.Meanwhile,the ratios of the above-ground biomass of AM tree species and ECM tree species in each quadrat to the total above-ground biomass in that quadrat were calculated as the biomass dominance values (R_AM/total and R_ECM/total) to characterize the relative biomass relationship between the two types of mycorrhizal tree species.Additionally,surface soil samples were collected from a depth of 0-20 cm for analysis of critical soil parameters:soil organic matter （SOM）,total nitrogen （TN）,total phosphorus （TP）,and available nutrient content.To evaluate overall soil fertility,the first principal component derived from the soil nutrient data was utilized.[Result]The results from the study revealed that mycorrhizal types significantly influence both the diversity and dominance of their associated tree species.Trees belonging to the AM category demonstrated markedly higher values in both the Simpson and Margalef indices compared with those of ECM trees.Furthermore,the diversity indices and biomass dominance of the AM and ECM types exhibited differential effects on soil nitrogen and phosphorus content.Specifically,the Margalef index and Pielou index for AM trees were found to have significant positive correlations with total phosphorus （TP） and available phosphorus （AP） content in the soil,respectively.In contrast,the biodiversity indices associated with ECM trees did not display similar correlations.Moreover,the ratio of AM tree AGB to total AGB (R_AM/total) showed a positive correlation with soil nitrate nitrogen （NO₃^--N） and available phosphorus （AP）.The analysis further indicated that increased diversity indices for both mycorrhizal types contributed to enhanced levels of soil fertility;However,it is noteworthy that R_AM/total did not exhibit significant correlations with soil fertility metrics.[Conclusion]In subtropical forests,both the diversity and biomass dominance of mycorrhizal trees have an impact on soil nutrients.Moreover,mycorrhizae influence this process by altering the above-ground biomass of symbiotic tree species rather than the diversity of mycorrhizal tree species.Although the diversity of mycorrhizal trees can affect soil fertility,it does not have a significant impact on this process.更多还原