杉木林转为油茶林对土壤细菌群落结构的影响

Effects of the conversion of Cunninghamia lanceolate plantations to Camellia oleifera plantations on the structure and diversity of soil bacterial community

【目的】研究杉木林转为油茶林后土壤细菌群落结构及多样性,为油茶林的可持续经营提供理论基础。【方法】通过高通量测序技术分析杉木林转为油茶林后土壤细菌群落结构及其与土壤理化性质的相关关系。【结果】杉木林和油茶林中共有OUT 2845个,30个门,88个纲,195个目,295个科和887个属。2种林分类型中主要细菌群落有变形菌门、酸杆菌门、绿弯菌门、放线菌门、浮霉菌门和Myxococcota,其中优势菌门为变形菌门、酸杆菌门和绿弯菌门,3个优势菌门的丰度占细菌总量的69.5%~73.9%。杉木林土壤中的变形菌门显著高于油茶林(P<0.05);而绿弯菌门和Myxococcota则显著低于油茶林(P<0.05);匿杆菌门、Spirochaetota、达达菌门和MBNT15为油茶林特有菌门。油茶林的土壤细菌多样性和丰度高于杉木林,杉木林的细菌物种在土壤中分布较油茶林更为集中,2种植被土壤中已鉴别出的优势菌属为Acidibacter、热酸菌属、短根瘤菌属,杉木林土壤中热酸菌属显著高于油茶林(P<0.05),而Bryobacter显著低于油茶林(P<0.05)。相关分析表明,土壤有效磷、碱解氮和含水率对细菌群落结构影响较大,在3个主要优势菌门中绿弯菌门与全氮极显著负相关(P<0.01),与土壤含水率、全磷、碱解氮和有机质显著负相关(P<0.05)。在油茶林特有菌门中匿杆菌门、达达菌门与速效钾分别呈极显著正相关(P<0.01)和显著正相关(P<0.05),而Spirochaetota与土壤有效磷极显著正相关(P<0.01)。【结论】以上结论表明林地植被类型转变对土壤细菌群落有显著影响,为了解杉木林转为油茶林土壤细菌群落组成及多样性提供理论依据,对于营造可持续发展的油茶林有重要参考价值。

【Objective】This work was aimed to explore the structure and diversity of soil bacterial community after the conversion of Cunninghamia lanceolate plantations to Camellia oleifera plantations,to provide a theoretical basis for the sustainable management of Camellia oleifera plantations.【Method】The physical and chemical properties of soil were measured and high-throughput sequencing technology was used to determine the structure and diversity of the soil bacteria community.The redundancy analysis(RDA)was used to examine the effects of physicochemical factors on the structure and diversity of the soil bacteria community.【Result】A total of 2845 operable taxonomic units(OTU)were obtained from sequencing technology,which belonged to 30 phyla,88 classes,195 orders,295 families and 887 genera.At the phylum level,Proteobacteria,Acidobacteria,Chloroflexi,Actinobacteria,Planctomycetes and Myxococcota were the 6 main bacterial communities,among which Proteobacteria,Acidobacteria and Chloroflexi were the dominant bacterial communities,accounting for 69.5%-73.9%of the total phylum in the 2 plantations.The relative abundance of Proteobacteria in the soil of Cunninghamia lanceolate plantations was relatively higher than that in Camellia oleifera plantations(P<0.05),while the relative abundance of Chloroflexi and Myxococcota showed an opposite trend(P<0.05).Latescibacteria,Spirochaetota,Dadabacteria and MBNT15 were distributed in Camellia oleifera plantations.The indicators for soil bacterial diversity were relatively higher in Camellia oleifera plantations than Cunninghamia lanceolate plantations.However,the distribution of bacterial community was more concentrated in Cunninghamia lanceolate plantations.Acidibacter,Cidothermus and Bradyrhizobium were the dominant bacterial genera that have been identified in those 2 plantations,Cidothermus had higher relative abundance in Cunninghamia lanceolate plantations than Camellia oleifera plantations(P<0.05),whereas Bryobacter had significantly lower relative abundance in Cunninghamia lanceolate plantations than Camellia oleifera plantations(P<0.05).Redundancy analysis showed that available phosphorus,nitrogen hydrolysis and soil water content had the greatest impact on the structure of soil bacterial community.Chloroflex was significantly negatively correlated with total nitrogen(P<0.01),water content,total phosphorus,nitrogen hydrolysis and organic matters(P<0.05).In the specific phyla of Camellia oleifera plantations,Latescibacteria and Dadabacteria were significantly positively correlated with available potassium(P<0.01,P<0.05),while Spirochaetota was significantly positively correlated with available phosphorus(P<0.01).【Conclusion】The results showed that the change of forest vegetation type has a significant impact on the soil bacterial community,which provides an important reference for the sustainable management of Camellia oleifera plantations.