华北落叶松-白桦混交林土壤细菌群落结构与多样性及其影响因素

Soil Bacterial Community Structure,Diversity and Its Influencing Factors in Larch and Birch Mixed Forest

为明确营造混交林对土壤细菌群落组成、多样性的影响及其驱动机制。采用高通量测序技术,分析内蒙古自治区兴和县苏木山林场华北落叶松-白桦混交林、自然恢复荒地土壤细菌多样性及物种组成,采用主坐标分析、线性判别分析(LEfSE)明确土壤细菌群落组成差异,采用方差分析、冗余分析阐明土壤养分对细菌群落分布的贡献率。结果表明:①放线菌门、变形菌门、酸杆菌门是混交林以及荒地表层(0<h≤20 cm)、底层(20 cm<h≤40 cm)土壤的优势门,黄色杆菌科、分枝杆菌属、慢生根瘤菌属是混交林地表层土壤的优势细菌类群,其相对丰度显著高于荒地土壤。②拟杆菌门、甲基肌酐门、粘球菌门、放线菌纲、甲基肌酐纲、红色杆菌纲、脱卤球菌纲、黄色杆菌科、Methyloligellaceae、红色杆菌科、Vicinamibacteraceae、慢生根瘤菌属、土微菌属、红杆菌属、Ilumatobacter为混交林地和荒地表层、底层土壤差异贡献率最大的细菌类群;细菌群落差异从大到小依次为混交林与荒地差异、土层差异。③土壤速效氮、有机质、碱性蛋白酶是影响混交林以及荒地表、底层土壤细菌群落结构的主要环境因子。华北落叶松-白桦混交林显著改变了土壤细菌群落结构,并且促进了参与土壤碳、氮、磷循环的细菌类群生长。

In order to clarify the effects of mixed forest construction on soil bacterial community composition,diversity and its driving mechanism.The high-throughput sequencing technology was used to analyze the bacterial diversity and composition of soil in the larch and birch mixed forest and naturally restored wasteland in Sumu Forest Farm,Xinghe County,Inner Mongolia.Principal co-ordinates analysis and LEfSE analysis were used to analyze the differences in soil bacterial community composition,and Variance analysis and Redundancy analysis were used to analyze the contribution of soil nutrients to bacterial community distribution.The results showed that(1)Actinobacteriota,Proteobacteria and Acidobacteriota were the dominant phyla in the surface(0<h≤20 cm)and bottom soil(20 cm<h≤40 cm)of mixed forest and wasteland.The dominant bacterial groups in the surface soil of mixed forest were Xanthobacteraceae,Mycobacterium and Bradyrhizobium,which the relative abundance were significantly higher than that in wasteland.(2)Bacteroidota,Methylomirabilota,Myxococcota,Actinobacteria,Methylomirabilia,Rubrobacteria,Dehalococcoidia,Xanthobacteraceae,Methyloligellaceae,Rubrobacteriaceae,Vicinamibacteraceae,Bradyrhizobium,Pedomicrobium,Rubrobacter and Ilumatobacter were the most differentiated bacterial group in surface and bottom soil of mixed forest and wasteland.The differences of bacterial communities from large to small were“the difference of mixed forest and wasteland”and“the difference of soil layer”.(3)Soil available nitrogen,organic matter and alkaline protease were the main environmental factors affecting the bacterial community structure in the surface and bottom soil of mixed forest and wasteland.The larch and birch mixed forest significantly changed the soil bacterial community structure,and promoted the growth of bacterial groups involved in soil carbon,nitrogen and phosphorus cycling.