摘要
【目的】氧化亚氮(nitrous oxide,N_(2)O)还原菌是已知唯一能够消除N_(2)O的微生物类群,其功能基因(nosZ)的丰度、多样性和群落结构及其影响因素对N_(2)O的去除具有重要意义。杉木是我国南方广泛种植的建材树种,其根际是N_(2)O产生和还原的热点区域。然而,杉木人工林根际土壤nosZⅠ基因的空间分布模式及其驱动因子仍不清楚。【方法】选取福建省5个国有林场(邱家山、五一、官庄、峡阳、霞浦)的杉木人工林根际土壤,利用荧光定量PCR和扩增子测序技术分析nosZⅠ基因的丰度、多样性及群落结构,并探讨其主要环境驱动因子。【结果】各林场根际土壤可溶性有机碳含量为6.91-23.52 mg/kg,其中官庄和峡阳林场的可溶性有机碳含量显著低于五一、邱家山和霞浦;各林场根际土壤nosZⅠ基因丰度为4.76×10^(6)-36.50×10^(6)copies/g,其中官庄和峡阳林场的nosZⅠ基因丰度分别为36.50×10^(6)copies/g和29.08×10^(6)copies/g,显著高于邱家山、五一及霞浦。可溶性有机碳是影响nosZⅠ基因丰度的关键因子,低可溶性有机碳环境可能促进N_(2)O还原菌的富集;各林场根际土壤nosZⅠ基因Shannon指数为4.41-5.67,峡阳的Shannon指数显著高于五一和霞浦,而霞浦的Shannon指数最低,土壤总碳是影响Shannon指数的关键因子;邱家山、官庄和霞浦的根际土壤nosZⅠ群落结构较为相似,而峡阳的nosZⅠ群落结构显著不同于其他林场。土壤p H是其主要驱动因子,且峡阳的土壤pH值显著高于其他林场;5个林场根际土壤优势菌纲均为γ-变形菌纲,而峡阳林场的γ-变形菌纲相对丰度显著低于其余林场,但α-变形菌纲相对丰度显著高于其余林场。【结论】土壤碳含量和pH是调控杉木人工林根际土壤N_(2)O还原菌丰度、多样性及群落结构的关键环境因子,可能影响N_(2)O的生物去除过程及其减排潜力。因此,在杉木人工林管理中应关注土壤碳含量和p H调控以优化N_(2)O的减排效应,缓解全球气候变化。
[Objective]Nitrous oxide(N_(2)O)-reducing microbes are the only known microbial group capable of eliminating N_(2)O.The abundance,diversity,community structure,and influencing factors of their functional gene(nosZ)are critical for N_(2)O removal.Cunninghamia lanceolata is a widely planted timber species in southern China,and its rhizosphere represents a hotspot for both N_(2)O production and reduction.However,the spatial distribution pattern of nosZⅠgenes and their driving factors in the rhizosphere soils of C.lanceolata plantations remain unclear.[Methods]We investigated the rhizosphere soils of C.lanceolata plantations from five state-owned forest farms—Qiujiashan,Wuyi,Guanzhuang,Xiayang,and Xiapu—in Fujian Province.Quantitative PCR and amplicon sequencing were employed to analyze the abundance,diversity,and community structure of nosZⅠgenes and to identify their key environmental drivers.[Results]Dissolved organic carbon concentrations in rhizosphere soils ranged from 6.91 mg/kg to 23.52 mg/kg,being significantly lower in Guanzhuang and Xiayang than in Wuyi,Qiujiashan,and Xiapu.The nosZ I gene abundance ranged from 4.76×10^(6)copies/g to 36.50×10^(6)copies/g,reaching 36.50×10^(6)copies/g and 29.08×10^(6)copies/g in Guanzhuang and Xiayang,respectively,which significantly exceeded those in Qiujiashan,Wuyi,and Xiapu.Dissolved organic carbon emerged as the primary driver of nosZ I gene abundance,which implied that low dissolved organic carbon may promote the proliferation of N_(2)O-reducing bacteria.The Shannon index of nosZ I genes ranged from 4.41 to 5.67,being significantly higher in Xiayang than in Wuyi and Xiapu and the lowest in Xiapu.Total carbon was the key factor affecting the Shannon index.The nosZ I community structures in Qiujiashan,Guanzhuang,and Xiapu were similar,whereas that of Xiayang was significantly different from the others.Soil pH was identified as the main driver of community structure,and Xiayang had a significantly higher pH than the other sites.The dominant bacterial class in the rhizosphere soils of all five forest farms was Gammaproteobacteria.Xiayang had significantly lower relative abundance of Gammaproteobacteria but significantly higher relative abundance of Alphaproteobacteria than other farms.[Conclusion]Soil carbon content and pH are key environmental factors regulating the abundance,diversity,and community structure of N_(2)Oreducing bacteria in the rhizosphere soils of C.lanceolata plantations,potentially influencing N_(2)O removal and mitigation potential.Therefore,the management strategies for C.lanceolata plantations should consider regulating soil carbon content and pH to optimize N_(2)O mitigation effects and alleviate global climate change.
作者
李奎毅
郑勇
邓米林
叶桂萍
林永新
LI Kuiyi;ZHENG Yong;DENG Milin;YE Guiping;LIN Yongxin(Fujian Provincial Key Laboratory for Subtropical Resources and Environment,Fujian Normal University,Fuzhou,Fujian,China;School of Geographical Sciences,Fujian Normal University,Fuzhou,Fujian,China;South China Botanical Garden,Chinese Academy of Sciences,Guangzhou,Guangdong,China;College of Geography and Oceanography,Minjiang University,Fuzhou,Fujian,China)
出处
《微生物学报》
北大核心
2025年第12期5469-5481,共13页
Acta Microbiologica Sinica
基金
国家自然科学基金(42377301)
福建省林业科技项目(2024FKJ33)
闽江学院引进人才预研项目(MJY20012)。
