生态恢复模式对若尔盖高寒沙化草地土壤微生物群落功能多样性的影响

若尔盖高原生态战略地位突出,在维持地区生物多样性、生态系统稳定等方面起到重要作用.研究不同生态恢复模式下土壤微生物群落功能多样性,有助于为在高寒草地以及全国其他类似地区实施退牧还草、退耕还林还草等生态环境重建工作提供科学依据.以若尔盖草地不同恢复模式下的土壤微生物群落为研究对象,采用Biolog微平板法对比研究了生态治...     

土壤多功能性对微生物多样性降低的响应

土壤微生物群落在驱动多种生态系统功能和生态过程中发挥着重要作用,是维持生物地球化学循环的主要驱动力.鉴于全球背景下观察到土壤微生物多样性随着土地利用集约化、气候变化而降低的现象,对土壤微生物多样性的减少是否会对土壤多功能性产生影响进行调查显得尤为重要.利用稀释灭绝法构建土壤微生物多样性梯度,结合高通量测序等技术手段,探究细菌、真菌和原生生物多样性降低对土壤多功能性的影响.结果表明,与未灭菌土壤相比,稀释处理土壤微生物α多样性（丰富度指数和香农指数）显著降低.主坐标分析（PCoA）表明,未灭菌土壤微生物群落结构与稀释处理土壤存在显著分异,而且细菌和真菌群落对稀释处理的响应高于原生生物.回归模型显示,土壤多功能性与微生物多样性指标呈显著的负线性关系,表明土壤微生物群落变化是调节土壤多功能性的关键因素.其次,通过集成推进树（ABT）和回归模型预测分析发现,一些特定的微生物类群如真菌短柄菌属（Solicoccozyma）、瓦湖胶珊瑚菌（Holtermanniella）和细菌属Rudaea相对丰度与土壤多功能性显著负相关,说明关键微生物类群在生物过程中发挥了指示性作用.进一步通过结构方程模型揭示,细菌、真菌和原生生物多样性都对土壤多功能性存在直接或间接影响,其中细菌是驱动土壤多功能性变化的关键生物因子.研究为土壤微生物多样性对土壤多功能性的影响提供了试验证据,并认为在单一农业生态系统中维持一定的土壤微生物群落多样性,特别是关键微生物类群的多样性对未来生态系统功能的可持续发展具有重要意义.     

黑河上游不同植被类型土壤细菌群落多样性、功能及季节动态

土壤微生物群落与植物群落间的作用机制是探究生物地球化学循环过程和维持植被生态系统稳定的关键.黑河上游植被的垂直分布特征明显,选取垫状植被（CV）、灌丛草甸（HM）、森林草原（FS）、山地干草原（MS）和荒漠草原（DG）共5种典型植被样地,运用高通量测序技术分析冬、夏季不同植被类型土壤细菌的群落结构和多样性,基于FAPROTAX数据库进行群落功能预测,运用冗余分析、结构方程模型探讨驱动土壤细菌群落的主要环境因子,并揭示细菌群落变化的作用机制与季节差异.结果表明：①不同植被类型和季节下土壤理化性质差异显著,各指标随土壤深度的变化规律不同,森林草原（FS）的土壤含水率和碳氮养分含量更高;②细菌群落α-多样性指数在季节间的差异（P<0.05）大于植被类型（P>0.05）,冬季群落丰度整体高于夏季,物种多样性在冬季随海拔呈"倒U "型分布,夏季呈" W"型分布;③细菌群落结构和组成在门水平上无显著差异,优势种群为酸杆菌门（Acidobacteria）、变形菌门（Proteobacteria）和放线菌门（Actinobacteria）,但在属水平上随季节有明显不同;④土壤细菌群落的功能随植被类型和季节变化较小,均以化能异养、硝化和氨氧化作用为主;⑤影响细菌群落的关键因子存在季节差异,冬季为土壤温度（ST）、总有机碳（TOC）和pH,夏季为土壤含水率（SWC）、碳氮比（C/N）和pH;⑥土壤细菌群落受彼此关联的环境因子的协同作用,土壤理化性质对细菌群落多样性和功能的影响较植被类型更直接,改善土壤的碳、氮水平有助于提升细菌的物种和功能多样性.研究结果可为探索区域植被退化机制和维持高寒生态系统稳定提供参考.     

荒漠绿洲土壤抗生素抗性基因分布特征及驱动机制

荒漠绿洲农田生态系统是干旱区环境下人类活动显著的复合生态系统.土壤微生物抗生素抗性与人类健康和生态平衡关系密切.研究荒漠绿洲环境不同土地利用类型模式下土壤抗生素抗性基因的多样性、分布特征和影响因素,对于评估干旱区土壤环境健康风险,促进绿洲农业生态的发展具有重要意义.采用高通量测序和高通量定量PCR技术对荒漠绿洲土壤微生物的群落结构和抗生素抗性基因多样性开展了研究,旨在探究干旱区土壤抗性基因的分布特征及其驱动机制.结果表明,从沙漠边缘到绿洲,荒漠沙生植物土壤、棉花地土壤、玉米地土壤、芦苇地土壤和湖泊沉积物中抗生素抗性的种类和丰度显著增加,与土地利用变化关系密切,农田土壤是抗性基因的重要存储库;荒漠绿洲土壤微生物群落与抗生素抗性基因显著相关,硫杆菌属(Thiobacillus)、沙漠细菌属(Pontibacter)、诺卡氏菌属(Nocardioides)、耐盐微杆菌属(Salinimicrobium)、土壤红杆菌属(Solirubrobacter)和链霉菌属(Streptomyces)等是各类抗性基因重要的潜在携带者;干旱区土壤中重(类)金属元素和可移动基因元件,与微生物群落共同塑造了抗生...     

戴云山南坡不同海拔森林土壤微生物群落结构特征和影响因素

土壤微生物作为森林生态系统主要驱动力,是影响生态系统物质循环和养分转化的重要因素.探讨不同海拔和季节森林土壤微生物群落的分布规律,对理解土壤生态过程和预测土壤生态系统功能具有重要研究意义.以戴云山南坡不同海拔森林土壤(海拔900～1 500 m)为研究对象,探讨夏季和冬季不同海拔土壤微生物群落结构和功能多样性,揭示驱动土壤微生物群落变化的主要因素.结果表明：(1)夏季土壤微生物群落中革兰氏阳性菌含量最高,冬季土壤真菌含量最高,海拔1 200 m处土壤总磷脂脂肪酸含量均高于其它海拔.随海拔升高,冬季土壤微生物群落中土壤真菌群比细菌群占据更大优势.(2)冗余分析表明,夏季7个海拔土壤微生物群落磷脂脂肪酸(PLFA)含量主要受环境因子和地形因子共同作用,累计解释量达56.72%;冬季土壤微生物群落磷脂脂肪酸含量主要受环境因子驱动,单独解释量达52.23%,环境因子和地形因子累计解释量为55.37%.(3)土壤全碳含量、土壤pH和多酚氧化酶是驱动夏季土壤微生物群落变化的主要因子;土壤有效磷、全钾、全碳含量和土壤pH是驱动冬季土壤微生物群落变化的主要因子.     

铜尾矿库坝面土壤微生物群落动态的驱动因子

随机过程和确定性过程对群落动态的影响机制及重要性是群落生态学研究的中心课题,也是目前群落生态学最具争议的问题.微生物群落在生态系统物质循环和能量流动过程中发挥着重要作用,对其结构动态的研究不仅为阐明群落构建机制提供重要的数据支持,而且为预测环境胁迫条件下微生物群落结构的动态提供理论依据.本研究通过Illumina MiSeq测序的方法,分析了中条山十八河尾矿库坝面不同恢复阶段细菌和真菌群落结构特征.结果表明,研究区尾矿坝不同恢复年限土壤理化性质发生梯度变化,植物群落结构呈现一定的演替趋势,植物群落多样性与土壤养分显著相关,而与土壤重金属含量无相关性.不同恢复年限的土壤微生物群落结构具有显著差异,其中优势细菌主要有变形菌门（Proteobacteria）、放线菌门（Actinobacteria）、厚壁菌门（Firmicutes）、酸杆菌门（Acidobacteria）;优势真菌主要有子囊菌门（Ascomycota）、担子菌门（Basidiomycota）、接合菌门（Zygomycota）.微生物群落组成主要受到土壤养分和重金属含量的影响,而植物多样性对微生物群落结构的影响不明显,表明在局域小尺度环境胁迫条件下,土壤环境因子是微生物群落结构动态变化的主要驱动力.     

直流电场对根际土壤微生物群落的影响及其机理

电场作用下根际土壤微生物群落的变化与利用电场强化植物修复效率密切相关.文章利用改进的PCR-DGGE(多聚酶链式反应-变性梯度凝胶电泳)方法,研究了不同电场条件下根际土壤微生物群落多样性和相似性的变化,分析了直流电场对土壤微生物群落的影响机理.结果表明,电场对根际土壤微生物群落的影响与电场条件有关,合适的电场条件有助于增加土壤微生物群落的多样性,但是电场形式、强度和施加方式不当则会使土壤微生物群落的多样性和结构受到明显影响.电场作用下土壤性质的变化、电场对土壤微生物的迁移作用和致死效应、以及微生物对环境压力的生理响应等是电场影响土壤微生物群落的主要机制.为了避免电场对根际土壤微生物的不利影响,利用电场强化植物修复时需要采用合适的电场条件.     

酸性矿山废水对稻田土壤微生物菌群结构的影响

为探究酸性矿山废水(AMD)对稻田土壤微生物群落结构的影响,通过取自矿区受AMD污染和未受污染的稻田土壤进行微宇宙灌溉模拟实验,研究了AMD污染过程中土壤理化性质和微生物群落的变化,同时建立环境条件变化引起土壤微生物群落结构改变的相关性关系.结果表明,受AMD污染的土壤中SO_4~(2-)、Cd、Zn含量显著上升,土壤酸化且土壤中细菌群落的多样性下降;而恢复清洁水灌溉可提高土壤细菌群落的多样性,有利于修复AMD的污染.采用高通量测序技术分析了不同处理稻田土壤中微生物群落在门和属分类水平上的相对丰度分布变化,冗余分析(RDA)表明,土壤pH和重金属(Pb、Cu)含量是影响稻田土壤微生物群落结构的主要环境因子.研究结果不仅有助于进一步揭示AMD污染、土壤因子与土壤微生物群落的相互关系,同时可为恢复AMD污染农业土壤提供理论依据.     

北京城市发展对土壤微生物群落功能多样性的影响

为研究城市发展对土壤微生物功能多样性的影响,以北京市建成区为例,采用Biolog-ECO微平板技术分析不同环路内3种类型绿地(居民区内绿地、街道边绿地、公园内绿地)土壤微生物群落功能多样性的变化.结果表明:二环内各绿地类型土壤微生物群落的AWCD(average well color development,平均颜色变化率)相对较高,分别为1.107、1.192、1.007,表明其土壤微生物群落代谢活性较高,利用碳源能力较强,其他环路土壤微生物群落利用碳源能力相对较弱;其中,各绿地类型土壤微生物群落对羧酸类碳源的利用能力最弱.城市环路梯度下居民区对土壤微生物群落多样性的影响相对较大;街道对土壤微生物群落功能多样性无显著影响(或者城市环路梯度下街道边绿地土壤微生物群落功能多样性趋同);四环～五环公园内绿地土壤微生物群落功能多样性与其他环路之间存在显著差异.对土壤微生物群落碳源利用能力进行主成分分析的结果显示,居民区内绿地、街道边绿地、公园内绿地提取的与土壤微生物碳源利用相关的主成分累积贡献率分别为86.79%、87.09%、84.92%,对主成分分离起主要作用的碳源主要是氨基酸类、糖类、多聚物类和羧酸类物质.冗余分析(RDA)表明,pH、土壤含水量是影响土壤微生物群落代谢能力和功能多样性的主要因素.城市绿地类型和环路因子对土壤微生物利用碳源分异存在一定影响,但对碳源代谢能力变异的解释量(5.91%)低于土壤理化因子的解释量(16.26%).研究显示,城市环路对土壤微生物功能多样性产生一定影响,但各环路街道边绿地土壤微生物功能多样性无显著差异,并且二环内、二环～三环、三环～四环各绿地类型土壤微生物多样性也无显著差异,说明城市发展可能使土壤微生物群落功能多样性趋于同质化.      

模拟的增温增雨对内蒙古温带草原土壤氨氧化微生物的影响

土壤氨氧化微生物是草地生态系统氮循环过程特别是氨氧化过程的主要驱动者,对全球变化具有响应、适应和反馈机制.通过采集在内蒙古温带草原设置的长期增温增雨野外控制实验的土壤样品,应用定量PCR、限制性末端片段长度多态性(terminal restriction fragment length polymorphism,T-RFLP)和克隆文库等方法研究氨氧化古菌和细菌的丰度、多样性和群落结构对增温增雨的响应.结果表明,增雨显著升高了土壤pH,而增温显著降低了土壤呼吸.氨氧化微生物丰度在各处理之间没有显著差异.T-RFLP结果表明,增雨显著影响土壤氨氧化细菌的群落结构,增温和增雨对土壤氨氧化微生物群落结构的交互作用并不显著.结构方程模型的结果显示植物多样性与氨氧化古菌和细菌的群落结构有显著的相关关系,表明气候变化-微生物-植物三者之间存在着一定的关系.研究结果预示土壤微生物对长期气候变化有一定的适应能力,这对预测未来生态系统的变化具有重要的参考价值.     

Soil biodiversity for agricultural sustainability

We critically highlight some evidence for the importance of soil biodiversity to sustaining (agro-)ecosystem functioning and explore directions for future research. We first deal with resistance and resilience against abiotic disturbance and stress. There is evidence that soil biodiversity does confer stability to stress and disturbance, but the mechanism is not yet fully understood. It appears to depend on the kind of stress and disturbance and on the combination of stress and disturbance effects. Alternatively, community structure may play a role. Both possible explanations will guide further research. We then discuss biotic stress. There is evidence that soil microbial diversity confers protection against soil-borne disease, but crop and soil type and management also play a role. Their relative importance as well as the role of biodiversity in multitrophic interactions warrant further study. Henceforth, we focus on the effects of plant and soil biodiversity on nutrient and water use efficiencies as important ecological functions in agroecosystems. The available evidence suggests that mycorrhizal diversity positively contributes to nutrient and, possibly, water use efficiency. Soil fauna effects on nutrient and water use efficiencies are also apparent, but diversity effects may be indirect, through effects on soil structure. We present a conceptual diagram relating plant and soil biodiversity with soil structure and water and nutrient use efficiencies as a framework for future studies. We then consider how cropping systems design and management are interrelated and how management options might be interfaced with farmers’ knowledge in taking management decisions. Finally, we attempt to express some economic benefits of soil biodiversity to society as part of a wider strategy of conserving and using agrobiodiversity.     

A review of diversity-stability relationship of soil microbial community: What do we not know?

The impact of decreased biodiversity on ecosystem stability, or the diversity-stability (D-S) relationship, is one of the major concerns of modern ecological studies. Studies on the D-S relationship for soil microbial communities began in 2000 when the fumigation method was developed to generate different levels of soil microbial biodiversity. The studies used various measures and levels of biodiversity, and covered several functional parameters. Due to the lack of general concepts and reliable approaches to define microbial species, studies on the D-S relationship of soil microbial communities concentrate on genetic diversity and functional diversity more than species diversity. Contradictory results were observed in various studies on D-S relationship with possible factors affecting or even changing the directions of the D-S relationship including: (1) the methods of stability measurement, (2) the techniques in microbial diversity measurement, (3) the measures and levels of diversity, (4) the type and strength of disturbance, (5) the traits of functions, and (6) the hidden treatments stemming from diversity manipulation. We argue that future studies should take diversity, species composition and interaction, and soil environmental conditions holistically into account in D-S studies to develop modeling to predict soil functional stability. We also suggest that studies should be carried out on a wider range of disturbance types and functional parameters, and efforts be shifted towards long-term field studies.     

Communities of different plant diversity respond similarly to drought stress: experimental evidence from field non-weeded and greenhouse conditions

Accelerating rate of species loss has prompted researchers to study the role of species diversity in processes that control ecosystem functioning. Although negative impact of species loss has been documented, the evidence concerning its impact on ecosystem stability is still limited. Here, we studied the effects of declining species and functional diversity on plant community responses to drought in the field (open to weed colonization) and greenhouse conditions. Both species and functional diversity positively affected the average yields of field communities. However, this pattern was similar in both drought-stressed and control plots. No effect of diversity on community resistance, biomass recovery after drought and resilience was found because drought reduced biomass production similarly at each level of diversity by approximately 30?%. The use of dissimilarity (characterized by Euclidean distance) revealed higher variation under changing environments (drought-stressed vs. control) in more diverse communities compared to less species-rich assemblages. In the greenhouse experiment, the effect of species diversity affected community resistance, indicating that more diverse communities suffered more from drought than species-poor ones. We conclude that our study did not support the insurance hypothesis (stability properties of a community should increase with species richness) because species diversity had an equivocal effect on ecosystem resistance and resilience in an environment held under non-weeded practice, regardless of the positive relationship between sown species diversity and community biomass production. More species-rich communities were less resistant against drought-stressed conditions than species-poor ones grown in greenhouse conditions.     

土壤微生物多样性的主要影响因素

土壤微生物是土壤生态系统的主要组成部分,而且不同的土壤具有不同的土壤微生物群落。影响土壤微生物多样性的因素很多,主要可以分为自然因素和人为因素。本文将从土壤微生物多样性的影响因素的两个方面阐述目前国内外土壤微生物多样性的研究现状。     

土壤微生物多样性的主要影响因素

土壤微生物是土壤生态系统的主要组成部分。而且不同的土壤具有不同的土壤微生物群落。影响土壤微生物多样性的因素很多,主要可以分为自然因素和人为因素。本文将从土壤微生物多样性的影响因素的两个方面阐述目前国内外土壤微生物多样性的研究现状。     

Nitrogen deposition alters soil chemical properties and bacterial communities in the Inner Mongolia grassland

Nitrogen deposition has dramatically altered biodiversity and ecosystem functioning on the earth; however, its effects on soil bacterial community and the underlying mechanisms of these effects have not been thoroughly examined. Changes in ecosystems caused by nitrogen deposition have traditionally been attributed to increased nitrogen content. In fact, nitrogen deposition not only leads to increased soil total N content, but also changes in the NH₄⁺-N content, NO₃^--N content and pH, as well as changes in the heterogeneity of the four indexes. The soil indexes for these four factors, their heterogeneity and even the plant community might be routes through which nitrogen deposition alters the bacterial community. Here, we describe a 6-year nitrogen addition experiment conducted in a typical steppe ecosystem to investigate the ecological mechanism by which nitrogen deposition alters bacterial abundance, diversity and composition. We found that various characteristics of the bacterial community were explained by different environmental factors. Nitrogen deposition decreased bacterial abundance that is positively related to soil pH value. In addition, nitrogen addition decreased bacterial diversity, which is negatively related to soil total N content and positively related to soil NO₃^--N heterogeneity. Finally, nitrogen addition altered bacterial composition that is significantly related to soil NH₄⁺-N content. Although nitrogen deposition significantly altered plant biomass, diversity and composition, these characteristics of plant community did not have a significant impact on processes of nitrogen deposition that led to alterations in bacterial abundance, diversity and composition. Therefore, more sensitive molecular technologies should be adopted to detect the subtle shifts of microbial community structure induced by the changes of plant community upon nitrogen deposition.     

重金属复合污染农田土壤的微生物群落遗传多样性研究

采集了浙江省富阳市环山乡某冶炼厂小高炉附近受铜、锌、铅、镉不同程度复合污染的4个农田土壤样品，首先扩增土壤总DNA中的16S rDNA，然后进行变性梯度凝胶电泳(Denaturing Gradient Gel Electrophoresis)，分析了长期受重金属复合污染的农田土壤的微生物群落遗传多样性变化．结果表明，不同程度的重金属复合污染明显改变了农田土壤的微生物群落遗传多样性，但与多样性的改变不是简单的负相关关系，最大的多样性指数出现在中等污染程度的土壤中．     

重金属含量对城市土壤真菌群落结构的影响

作为土壤微生物系统的一个重要组成部分,真菌可以明显地对土壤环境的变化起到指示作用;城市中的人为活动很容易影响到土壤状况,因此城市土壤往往有人为重金属富集现象的出现.对城市内部不同功能区土壤中的真菌群落结构进行分析,旨在探明城市内部不同功能区中重金属含量对土壤真菌群落结构的影响,为城市土壤生态系统的修复与保护和城市环境质...