坡向对北亚热带大别山区不同马尾松林型土壤细菌群落的影响

Effects of slope aspect on soil bacterial communities in different forest types of Pinus massoniana in northern subtropical Dabie Mountains

土壤细菌作为土壤微生物的重要组成部分,在土壤生态系统中发挥着重要作用,作为北亚热带区典型的森林植被类型,马尾松针阔混交林在区域地带性植被恢复方面发挥着重要作用。探讨马尾松不同森林类型土壤细菌群落的组成结构和多样性特征是维护马尾松森林生态系统健康和稳定的关键。以北亚热带大别山区4种马尾松林型[马尾松(Pinus massoniana)纯林(pure forest,PF)、马尾松—麻栎(Quercus acutissima)混交林(Pinus mas-soniana-Quercus acutissima mixed forest,PQM)、马尾松—枫香(Liquidambar formosana)混交林(Pinus massoniana and Liquidambar formosana mixed forest,PLM)和马尾松—化香(Platycarya strobilacea)混交林(Pinus massoni-ana-Platycarya strobilacea,PPM)]为研究对象,分析不同坡向(阴坡和阳坡)下马尾松4种林型林地土壤细菌群落的组成及多样性变化规律,旨在为该区不同环境梯度下马尾松林的生产经营和生物多样性保护提供理论参考。结果表明:(1)马尾松4种林型林地共检测到36门107纲246目393科688属,其中土壤优势菌门为放线菌门(Actinobacteriota)、变形菌门(Proteobacteria)、酸杆菌门(Acidobacteriota)和绿弯菌门(Chloroflexi)。(2)3种马尾松针阔混交林土壤细菌丰富度和多样性在阴坡均显著高于马尾松纯林,且不同坡向变化为:阴坡>阳坡,而4种林型在阳坡差异不显著。(3)土壤含水量与土壤细菌门之间存在显著相关性,其中与细菌α多样性呈极显著正相关。综上,阳坡环境下,马尾松4种林型林地土壤细菌群落变化差异较小,相较于马尾松纯林,3种针阔混交林土壤细菌群落更易受不同坡向环境条件的变化而变化。坡向和林型变化引起的土壤含水量改变是导致北亚热带大别山区马尾松森林土壤细菌群落组成改变和多样性差异的主要因素。

Soil bacteria,as an important part of soil microorganisms,play an important role in soil ecosystem.As a typical forest vegetation type in northern subtropical region,Pinus massoniana coniferous and broad-leaved mixed forest plays an important role in regional zonal vegetation restoration.Explore the composition structure and diversity characteristics of soil bacterial communities in different types of forests is the key to maintain the health and stability of P.massoniana forest ecosystem.In this study,four forest types of Pinus massoniana(the pure forest of Pinus massoniana(PF),Pinus massoniana-Quercus acutissima mixed forest(PQM),Pinus massoniana and Liq-uidambar formosana mixed forest(PLM)and Pinus massoniana-Platycarya strobilacea(PPM))were selected from the Dabie Mountains of northern subtropical region as the research objects.To analyze the composition and diversity of soil bacterial communities in four P.massoniana forest types under different slope aspects(shady slope and sunny slope),so as to provide the theoretical reference for the production management and soil biodiversity protection of P.massoniana forest under different environmental gradients in this region.The results showed that:(1)Actinobacteria,Proteobacteria,Acidobacteria and Chloroflexi were the dominant bacteria in the soil in four different forest types of P.massoniana.(2)The soil bacterial richness and diversity of the three coniferous and broad-leaved mixed forests were significantly higher than that of the PF on the NW slopes,and the change of slope aspect was:shady slope>sunny slope,while the difference of the four forest types on the SE slope was not significant.(3)There was a signifi-cant correlation between soil water content and various bacterial phyla of soil in four types of P.massoniana forests,and it was also related to bacteriaαThe diversity was highly significant positive correlation.The comprehensive anal-ysis showed that the change of soil bacteria in the P.massoniana forests was less affected by the forest type in the sunny slope,and compared with the P.massoniana forests,the soil bacteria community under the three mixed conif-erous and broad-leaved forests was more easily affected by the slope direction to change;The change in soil water content caused by the change in slope aspect and forest type was the main reason for the change of composition and diversity of soil bacterial community in the P.massoniana forests in Dabie Mountain area,north subtropical China.