栗子坪自然保护区不同植被类型土壤理化特性对土壤微生物群落多样性的影响

The Impact of Soil Physicochemical Characteristics of Different Vegetation Types on Soil Microbial Community Diversity in Liziping Natural Reserve

在四川省栗子坪国家级自然保护区,选取青冈(Quercus glauca Thunb.)-川杨(Populus szechuanica C.K.Schneid.in Sargent)阔叶混交林、栓皮栎(Quercus variabilis Blume)落叶阔叶林、冷杉(Abies fabri(Mast.)Craib)-云杉(Picea asperata Mast.)针叶混交林、石棉玉山竹(Yushania lineolata T.P.Yi)竹林4个不同植被类型为研究样地,根据海拔高度、坡度、地形变化和样地大小等,在样地内设置1 m×1 m小样地,采集土壤样品,用于测定土壤含水率、测定土壤理化性质、土壤微生物群落构成;采用高通量测序法、单因素方差分析法、冗余分析(RDA)法、曼特尔(Mantel)检验,分析土壤微生物组成与土壤环境因子、土壤理化特性的相关性。结果表明:①4种林型土壤细菌Chao l指数和香农(Shannon)多样性指数均高于真菌,仅真菌的香农多样性指数差异显著。②门水平——细菌优势群落,主要为酸杆菌门(Acidobacteria,25.02%~41.81%)、变形菌门(Proteobacteria,28.68%~36.92%);真菌优势群落,主要为子囊菌门(Ascomycota,45.43%~57.37%)、担子菌门(Basidiomycota,19.61%~28.30%)、被孢霉门(Mortierellomycota,4.47%~16.96%)。③主坐标分析表明,4种林型土壤细菌的组内差异大于组间差异,真菌群落组间差异远大于组内差异。④曼特尔检验结果表明,土壤含水率、总有机碳质量分数、全氮质量分数、碳氮比(土壤碳质量分数(w(C))∶土壤氮质量分数(w(N)))对土壤真菌群落有显著影响,细菌群落受环境因子影响不大。⑤冗余分析结果表明,土壤含水率和非优势真菌球囊菌门(Glomeromycota)呈显著相关,土壤全氮质量分数、全磷质量分数均与优势菌担子菌门(Basidiomycota)呈显著正相关。不同植被类型的土壤微生物群落结构存在显著差异。

In the Liziping National Nature Reserve of Sichuan Province,four different vegetation types were selected as study plots:broad-leaved mixed forest(Quercus glauca Thunb.-Populus szechuanica C.K.Schneid.in Sargent),deciduous broad-leaved forest(Quercus variabilis Blume),coniferous mixed forest(Abies fabri(Mast.)Craib-Picea asperata Mast.),and bamboo forest(Yushania lineolata T.P.Yi).Based on altitude,slope,topographic variation,and plot size,1 m×1 m small sample plots were established within each study plot to collect soil samples for determining soil moisture content,soil physicochemical properties,and soil microbial community composition.High-throughput sequencing,one-way ANOVA,redundancy analysis(RDA),and Mantel test were used to analyze the correlation between soil microbial composition,soil environmental factors,and soil physicochemical properties.The results showed that:(1)The Chao1 index and Shannon diversity index of soil bacteria in the four forest types were higher than those of fungi,with only the Shannon diversity index of fungi showing significant differences.(2)At the phylum level,the dominant bacterial communities were mainly Acidobacteria(25.02%-41.81%)and Proteobacteria(28.68%-36.92%),while the dominant fungal communities were mainly Ascomycota(45.43%-57.37%),Basidiomycota(19.61%-28.30%),and Mortierellomycota(4.47%-16.96%).(3)Principal coordinate analysis showed that the within-group variation of soil bacterial communities was greater than the between-group variation,whereas the between-group variation of fungal communities was significantly greater than the within-group variation.(4)The Mantel test results showed that soil moisture content,total organic carbon content,total nitrogen content,and the carbon-to-nitrogen ratio soil carbon content(w(C))∶soil nitrogen content(w(N))had a significant impact on soil fungal communities,while bacterial communities were less affected by environmental factors.(5)Redundancy analysis indicated that soil moisture content was significantly correlated with the non-dominant fungal phylum Glomeromycota,and total nitrogen and phosphorus contents were significantly positively correlated with the dominant phylum Basidiomycota.There were significant differences in the soil microbial community structure among different vegetation types.