近自然管理方式对橡胶林根际土壤真菌群落结构和多样性的影响

【目的】探究近自然管理后橡胶林土壤、根际和根表中真菌物种组成和多样性变化,为橡胶林生物多样性恢复和天然橡胶的可持续发展提供理论基础。【方法】在试验场内建立1 ha橡胶林固定样地进行近自然管理,同时建立常规处理和除草剂处理的样地进行对比,基于高通量测序的方法分析土壤、根际及根表中真菌群落结构、多样性和群落功能。【结果】橡胶林进行近自然管理和除草剂处理后,其土壤有机质和全磷含量降低,近自然管理后pH和含水率升高。常规林、近自然管理林和除草剂处理林土壤、根际和根表的主要优势真菌类群是子囊菌门(Ascomycota)和担子菌门(Basidiomycota);近自然管理后橡胶林土壤中子囊菌门减少,根际和根表中子囊菌门增加。在OTU水平上进行PCoA分析,土壤和根表中物种组成存在显著差异(P<0.05)。3种橡胶林土壤、根际和根表中真菌的α多样性无显著差异(P>0.05);在OTU水平上的γ多样性分析,根表中近自然管理林的真菌物种总量高于常规林和除草剂处理林;RDA分析结果表明土壤、根际和根表中主要环境影响因子分别为pH、全氮和有机质。通过FUNGuild功能预测,3种橡胶林土壤、根际及根表真菌群落的营养型以腐生营养型为主,土壤中腐生营养型真菌含量高于根际和根表,近自然管理后橡胶林土壤中腐生营养型真菌减少。【结论】近自然管理方式后橡胶林土壤理化性质和养分发生改变,在一定程度上影响真菌的群落结构和多样性,同时增加了土壤中真菌在根表上的富集。

Effects of close-to-natural management on the community structure and diversity of fungi in the rhizosphere soil of rubber plantation

【Objective】To explore the changes in the composition and diversity of fungal species in the soil,rhizosphere and root surface of rubber plantations after close-to-natural management,so as to provide a theoretical basis for the restoration of rubber plantation biodiversity and the sustainable development of natural rubber.【Method】A fixed sample plot of 1 ha rubber plantation in the test site for close-to-natural management was established,at the same time,a sample plot of conventional treatment and a sample plot of herbicide treatment for comparative research were established to analyze the composition,diversity and community function of fungi in soil,rhizosphere and rhizoplane based on highthroughput gene sequencing.【Result】After close-to-natural management and herbicide treatment,the content of SOM and TP decreased,and the p H and water content increased. Ascomycota and Basidiomycota were the main dominant fungal groups in conventional plantation,near natural management plantation and herbicide treated plantation. After close-tonatural management,Ascomycota in rubber plantation soil decreased,and Ascomycota in rhizosphere and rhizoplane increased. PCoA analysis at OTU level showed that significant differences existed in species composition between soil and root surface(P<0.05). No significant difference in α diversity was found in fungi in soil,rhizosphere and rhizoplane of three rubber plantations.γ diversity analysis at OTU level showed that the total amount of fungal species in close-to-natural management plantation was higher than that in conventional plantation and herbicide treated plantation. RDA analysis showed that the main environmental impact factors in soil,rhizosphere and root surface were pH,TN and SOM. According to the functional prediction of FUNGuild,the main nutrient type of fungal communities in the soil,rhizosphere and rhizoplane of the three rubber plantations was saprophytic,and the content of saprophytic fungi in the soil was higher than that in the rhizosphere and rhizoplane. After close-to-natural management,the saprophytic fungi in rubber plantation soil decreased.【Conclusion】After near natural management,the water content and organic matter content of rubber forest increase,and the change of soil physical and chemical properties will influence the community structure and diversity of fungi to a certain extent,and increase the enrichment of fungi on the root surface.