西南地区马尾松与乡土阔叶树种凋落叶混合分解过程中的细菌群落特征  

Bacterial Community Characteristics during the Mixed Decomposition of Litter from Pinus massoniana and Indigenous Broad-leaved Tree Species in Southwestern China

作　　者：李勋 张艳 宋思梦 周扬 张健[2] LI Xun;ZHANG Yan;SONG Simeng;ZHOU Yang;ZHANG Jian(Research Center for Ecological Restoration and Characteristic Industry Cultivation in Hengduan Mountains Region/Research Center of Forest-Grass Care and Use in Sichuan-Tibet-Yunnan-Qinghai,Sichuan Minzu College,Kangding 626001,P.R.China;Key Laboratory of Forestry Ecological Engineering in Sichuan/Collaborative Innovation Center of Ecological Security in the Upper Reaches of Yangtze River,Sichuan Agricultural University,Chengdu 611130,P.R.China)

机构地区：[1]四川民族学院横断山区生态修复与特色产业培育研究中心/川藏滇青林草抚育和利用研究中心,四川康定626001 [2]四川农业大学林学院生态林业工程重点实验室/长江上游生态安全协同创新中心,四川成都611130

出　　处：《生态环境学报》2024年第1期12-27,共16页Ecology and Environmental Sciences

基　　金：四川省科技计划项目(2023NSFSC1168);国家自然科学基金项目(31370628);甘孜州科技计划项目(220030)。

摘　　要：林地内凋落叶的种类和比例调控其分解过程中微生物的群落结构。然而,不同树种组合以及不同混合比例的凋落叶在分解过程中细菌群落结构有何差异,目前尚不清楚。将马尾松与乡土阔叶树种香椿[Toona sinensis(A.Juss.)Roem.]、香樟(Cinnamomum camphora Linn.)和檫木(Sassafras tzumu Hemsl.)凋落叶按照不同树种、不同质量比例混合后,通过Illumina Mi Seq高通量测序研究凋落叶分解过程中细菌群落结构的动态变化特征。结果表明,在所有处理中,Proteobacteria和Actinobacteria均为优势门,Sphingomonas,unidentified_Rhizobiaceae,Bradyrhizobium和unidentified_Cyanobacteria为优势菌属。此外,混合凋落叶中细菌的多样性和丰富度在分解250 d后表现出较强的协同效应(分别为70.97%和29.03%);第2年分解期内大部分混合凋落叶的观测值-期望值<0,尤其是分解末期(分解604 d)后有19.35%的混合凋落叶的细菌多样性指数和9.68%的混合凋落叶的细菌丰富度指数表现出拮抗效应。不同树种组合凋落叶中,马尾松+香樟+香椿组合(PCT)下阔叶占比为30%-40%时更有利于提高细菌的多样性和丰富度。综上,凋落叶中细菌的多样性和丰富度受到分解时期和树种组合的共同影响。在后期马尾松纯林的“混交化”改造过程中,适当引入乡土阔叶树种香樟与香椿可增加马尾松林地内凋落叶中细菌的多样性和类群丰度。Tree species diversity in forest ecosystems not only controls the diversity and proportion of litter but also affects the microbial community residing in decomposed litter.However,the differences in the bacterial community structure in the process of leaf litter decomposition with different tree species combinations and mixed proportions are still unclear.In this study,a mixture of litter from Pinus massoniana and native broad-leaved tree species,including Toona sinensis(A.Juss.)Roem.,Cinnamomum camphora Linn.,and Sassafras tzumu Hemsl.,were created based on various tree species and their corresponding mass proportions.This study utilized Illumina MiSeq high-throughput sequencing to examine the dynamic features of the bacterial community structure during leaf litter decomposition.Proteobacteria and Actinobacteria were the dominant bacterial groups in all the treatments.The dominant genera were Sphingomonas,unidentified Rhizobiaceae,Bradyrhizobium,and unidentified Cyanobacteria.Overall,the diversity and richness of the bacteria in the mixed litter showed a strong synergistic effect after 250 days of decomposition(70.97%and 29.03%,respectively),whereas during the second year of decomposition,most of the observed values for the mixed litter were less than 0.Especially in the late decomposition stage,the bacterial diversity index of 19.35%mixed litter andbacterial richness index of 9.68%mixed litter showed antagonistic effects.Among different tree species combinations,the combination of P.massoniana+C.camphora+T.sinensis(PCT)with a broad-leaved ratio of 30%‒40%is more conducive to improving the diversity and relative richness of bacterial species in leaf litter.In summary,the diversity and richness index of bacteria in leaf litter were comprehensively influenced by the decomposition period and tree species combination.In the later stage of the transformation of low-efficiency artificial pure P.massonianaforests,C.camphora and T.sinensis could be planted to transform monoculture P.massoniana forests into mixed fores

关 键 词：混合凋落叶 细菌 马尾松 高通量测序 非加性效应 

分 类 号：S718.5[农业科学—林学] X171.1[环境科学与工程—环境科学]