浙江九龙山香果树生境土壤微生物多样性及其影响因素

Soil microbial diversity and its influencing factors in the habitat of rare plant Emmenopterys henryi in Jiulongshan,Zhejiang Province

【目的】揭示珍稀植物香果树Emmenopteryshenryi生境土壤微生物多样性变化信息及其影响因素,为香果树的保护和繁育提供参考。【方法】通过高通量测序技术检测了34个香果树群落生境的土壤细菌和真菌种类,分析海拔、坡向、土壤理化性质和香果树群落特征对土壤细菌和真菌多样性的影响。【结果】α多样性分析表明:九龙山香果树生境土壤细菌Shannon-Wiener指数均值为5.87,Simpson指数均值为0.98;土壤真菌Shannon-Wiener指数均值为4.88,Simpson指数均值为0.97。细菌Shannon-Wiener指数当量(H')随海拔升高而显著降低(P<0.05),随土壤pH(4.62~5.83)升高而显著升高(P<0.05);土壤细菌Simpson指数当量(D')与土壤速效钾呈显著负相关(P<0.05)。真菌H'和D'都随着海拔上升呈先下降后上升的趋势,且随碱解氮的升高而显著降低(P<0.05);真菌D'还与样地中心香果树胸高断面积呈显著正相关(P<0.05)。β多样性分析表明:细菌Sorenson相异性指数均值为0.39,其中物种周转组分贡献为70.2%,真菌Sorenson相异性指数均值为0.72,其中物种周转组分贡献为85.1%;细菌和真菌的Sorenson相异性指数各自存在显著空间自相关(P<0.05),且与土壤理化性质以及树种组成差异显著相关(P<0.05)。偏Mantel检验结果表明:细菌的物种周转组分与土壤理化性质和样地树种组成显著相关(P<0.05),而其物种丰富度组分仅与取样年份显著相关(P<0.05);真菌的物种周转组分存在显著空间自相关且与土壤理化性质差异显著相关(P<0.05),而其物种丰富度组分与取样年份、海拔都显著相关(P<0.05)。【结论】九龙山香果树生境土壤真菌多样性较高,细菌多样性较低;香果树生境土壤微生物多样性存在时空异质性,海拔、土壤碱解氮和香果树胸高断面积是土壤微生物α多样性的主要影响因素,土壤理化性质和样地树种组成是土壤微生物β多样性的主要影响因素。图4表2参32.

[Objective]This study,with an investigation into the temporal and spatial changes of soil microbial diversity in the habitat of the rare plant Emmenopterys henryi and the main controlling factors of these changes,is aimed to provide reference for the protection and breeding of the rare species.[Method]High throughput sequencing technology was used to detect operatonal taxonomic units(OTUs)of bacteria and fungi in soil from 34 E.henryi dominated stands before an analysis was conducted of the effects of altitude,slope direction,soil nutrition,and characteristics of the tree communities on the diversities of soil bacteria and fungi.[Result]αdiversity analysis indicated that the mean of Shannon-Wiener index of bacterial communities was 5.87,and that of fungal communities was 0.98;the numbers equivalent of Shannon-Wiener index(H')decreased significantly with the increase of altitude(P<0.05)and increased significantly with the increased soil pH(4.62-5.83)(P<0.05);meanwhile,the numbers equivalent of Simpson index(D')was significantly and negatively correlated with the content of available potassium in soil(P<0.05);H'and D'of soil fungi firstly decreased and then increased with the increased altitude,and significantly decreased with the increased alkali-hydrolyzed nitrogen content in soil(P<0.05);meanwhile,there was a significant and positive correlation between D'and the basal area of the central E.henryi tree(P<0.05).βdiversity analysis indicated that the mean Sorenson index of bacterial communities was 0.39,with 70.2%contributions of species turnover component,and that of fungal communities was 0.72,with 85.1%contributions of species turnover component;the Sorenson indices of soil bacterial and fungal communities were both significantly spatial auto-correlated(P<0.05),and correlated with differences in soil nutrient content and tree species composition.The partial Mantel test results indicated that:the species turnover components of bacteria were significantly correlated with differences in soil nutrient content and tree species composition(P<0.05),while the species richness difference of soil bacteria was significantly correlated with the difference in sampling year(P<0.05);the species turnover components of fungi were significantly spatially auto correlated(P<0.05),and correlated with differences in soil nutrient content,while the species richness difference of fungi was significantly correlated with the differences in sampling year and the altitude(P<0.05).[Conclusion]Compared with other forests in China,the habitat of E.henryi in Jiulongshan boasts more diverse soil fungal,less diverse soil bacterial and higher spatiotemporal heterogeneity in soil microbial diversity.Altitude,soil alkaline nitrogen content,and the size of E.henryi tree are the main factors affectingαdiversity of soil microbes,while soil physicochemical properties and the composition of tree communities are the main factors that influenceβdiversity of soil microbes.[Ch,4 fig.2 tab.32 ref.]