模拟大气氮沉降对不同树种土壤微生物生物量的影响

土壤微生物是土壤生态系统的重要组成成分,又是土壤肥力的重要评价指标之一,在生态系统物质循环和能量流动中起着重要作用。氮沉降影响土壤微生物生长和繁殖,使其结构和功能发生改变,从而影响土壤物质循环和能量流动。通过室内模拟自然氮沉降,运用磷脂脂肪酸技术,研究氮沉降对不同树种(荷木Schima superba、马尾松Pinus massoniana、马占相思Acacia mangium、海南红豆Ormosia pinnata)土壤微生物的影响。结果表明:自然氮沉降条件下,细菌是土壤微生物的主要类群,占土壤微生物总量的40%以上。采样时间和树种均对总土壤微生物生物量、细菌生物量有显著影响。同一树种10月土壤微生物生物量(总土壤微生物、细菌、真菌、放线菌)高于4月。4月土壤微生物生物量马占相思最高(总土壤微生物生物量76.78 nmol·g-1、细菌生物量33.94 nmol·g-1、真菌生物量6.91 nmol·g-1、放线菌生物量8.38 nmol·g-1),荷木最低(总土壤微生物生物量57.89 nmol·g-1、细菌生物量24.79 nmol·g-1、真菌生物量4.16 nmol·g-1、放线菌生物量5.57 nmol·g-1);10月海南红豆最高(总土壤微生物生物量92.67 nmol·g-1、细菌生物量38.85 nmol·g-1、真菌生物量8.09 nmol·g-1、放线菌生物量9.27 nmol·g-1),荷木最低(总土壤微生物生物量71.10 nmol·g-1、细菌生物量30.79 nmol·g-1、真菌生物量4.90 nmol·g-1、放线菌生物量7.04 nmol·g-1)。采样时间和树种的交互作用对放线菌生物量有显著影响。总土壤微生物生物量与铵态氮显著正相关,而真菌生物量与土壤有机质显著正相关。结果对全球变化条件下生态系统健康管理具有重要意义。     

陆地生态系统植物和土壤微生物群落多样性对全球变化的响应与适应研究进展

生态系统植物和土壤微生物群落多样性受氮沉降、气候变暖、大气CO_2浓度升高(eCO_2)、极端干旱等全球变化的强烈影响,深入认识和理解全球变化下植物群落-土壤微生物群落的关系对生物多样性保护至关重要。文章综述了陆地生态系统植物和土壤微生物群落多样性对以上4种全球变化单因子和多因子(双因子、三因子及四因子)交互作用的响应与适应规律。主要结论为,(1)氮沉降、气候变暖和极端干旱均改变了植物和土壤微生物的群落组成,呈现降低、增加和无影响3种效应,大多数研究结果是降低效应,例如高氮沉降和长期低水平氮沉降减少了植物多样性,微生物群落多样性的下降幅度随氮沉降时间和量的增加而加强;气候变暖改变了植物的物候,降低了植物多样性,促使土壤微生物群落的演替分异;极端干旱导致植物组成发生了方向性的变化,植物多样性降低并促进盐生植物的生长,土壤微生物量和活性降低并促使转向渗透胁迫型策略。(2)eCO_2增加促进植物光合作用从而刺激植物的生长,对植物多样性的影响取决于资源可利用性,一般增加根际细菌和土壤真菌的相对丰度以加快土壤的碳源利用。(3)全球变化多因子交互作用下植物-土壤微生物群落多样性的关联效应主要为协同、累加、抵消或非加性等,其中氮沉降×气候变暖为累加;氮沉降×eCO_2对植物生物量的影响为协同增效,而对植物群落可能是相反或抵消;气候变暖×eCO_2对土壤微生物群落为累加;三因子和四因子交互作用对植物和土壤微生物群落为非加性,较难预测。最后指出当前的研究不足和今后的发展方向:(1)加大不同时空尺度的植物和土壤微生物群落研究;(2)精确全球变化多因子交互作用对植物和土壤微生物群落多样性影响的估算。     

增温对南亚热带季风常绿阔叶林土壤微生物群落的影响

土壤微生物是森林生态系统中重要的分解者,参与生物圈的物质循环和能量流动,对温度变化响应较为敏感。以鼎湖山南亚热带季风常绿阔叶林为研究对象,基于野外增温实验平台,采集0-10 cm和10-20 cm土层的土壤样品,采用磷脂脂肪酸(PLFA)方法并结合土壤理化性质的监测,探究气温上升对土壤微生物群落的影响。结果表明:(1)增温处理使0-10 cm和10-20 cm土层月均温分别显著上升1.24℃和1.17℃,土层湿度变化不显著;(2)增温显著增加了土壤硝氮含量,但对其他理化性质作用不明显;(3)增温组土壤微生物生物量碳(MBC)、微生物生物量氮(MBN)、微生物生物量碳氮比(C/N)以及微生物总磷脂脂肪酸含量与对照组差异不显著;(4)增温显著改变了土壤微生物群落结构,使细菌相对丰度、细菌真菌之比(B/F)以及革兰氏阳性菌革兰氏阴性菌之比(G~+/G~-)显著增加,降低了真菌和丛枝菌根真菌的相对丰度;(5)进一步分析表明,土壤硝态氮和有机碳是影响土壤微生物群落结构变异的主要因子,两者共同解释了微生物群落结构60.5%的变异度。以上研究结果表明,尽管增温对南亚热带季风常绿阔叶林土壤微生物生物量作用不明显,但可通过对土壤硝氮和土壤有机碳含量的影响引起土壤微生物群落结构及其相对丰度的改变,微生物群落结构和相对丰度的变化又将通过影响微生物对土壤碳氮的同化作用,最终影响土壤的碳氮过程。     

黄土高原土壤细菌和真菌群落结构及其多样性对菌糠有机肥响应机制研究

为了明确黄土高原农田土壤细菌群落和真菌群落对菌糠有机肥的响应机制,基于高通量测序技术,分析了施用菌糠有机肥和施用化肥(对照)后土壤细菌和真菌群落物种组成、多样性指数、群落结构差异及其主要分异作用的微生物.结果表明,土壤细菌和真菌群落对外源养分的响应机制不同.添加菌糠有机肥改变了土壤细菌菌群的结构,厚壁菌门、奇古菌门相对...     

施氮对不同有机碳水平桉树林土壤微生物群落结构和功能的影响

碳、氮是影响土壤微生物群落结构和功能的2种重要生源要素,但研究施氮对人工林土壤微生物群落影响时很少考虑土壤有机碳水平。本研究以我国南方桉树Eucalyptus人工林为对象,研究施氮水平(对照:0 kg·hm-2,常规施氮水平166.8kg·hm-2,施二倍氮素水平333.7 kg·hm-2)对不同有机碳水平桉树林土壤微生物群落结构(磷脂脂肪酸构成)和功能(土壤酶活性及可溶性土壤有机碳含量)的影响,结果表明:施氮显著降低土壤微生物群落磷脂脂肪酸总量以及细菌、真菌、放线菌磷脂脂肪酸量和真菌/细菌比值(P0.05);区分不同处理的土壤微生物磷脂脂肪酸主要是:真菌特征脂肪酸16:1ω5c、18:1ω9c、18:2ω9c及细菌特征脂肪酸16:1ω7c、i17:0和放线菌特征脂肪酸10Me18:0;施氮显著增加了土壤纤维素酶、酚氧化酶活性及土壤可溶性有机碳含量(P0.05);尽管高土壤有机碳水平样地的土壤微生物磷脂脂肪酸量、土壤酶活性以及可溶性有机碳含量显著高于低土壤有机碳水平样地,但低、高土壤有机碳水平样地的土壤微生物群落结构和功能对施氮的响应不一致,土壤细菌、真菌、放线菌磷脂脂肪酸量以及酚氧化酶活性和土壤可溶性有机碳含量在低土壤有机碳水平样地中对施氮的响应更敏感,而这些指标在高土壤有机碳水平样地中只有在施二倍氮素处理中才显著降低或不变化。该研究结果表明不同土壤有机碳水平中的土壤微生物群落对施氮的响应不一致,强调了在全面认识氮肥施用对土壤微生物群落的影响时,需要充分考虑土壤有机碳水平。     

重金属污染降低水稻土微生物商并改变PLFA群落结构——苏南某地污染稻田的案例研究

重金属污染可能影响土壤中微生物生物量与活性及群落结构.但这种影响随土地利用和土壤类型、污染物类型而异.采集了江苏南部某市金属冶炼产业区周边重金属污染的稻田和未明显污染稻田的表土样品,分析了重金属复合污染下土壤微生物生物量以及PLFA群落结构的变化.结果表明,重金属污染下稻田土壤的微生物生物量碳、氮及微生物商比未明显污染的土壤显著降低(约20%);PLFA分析显示,重金属污染下土壤微生物群落结构发生了明显的变化,细菌和真菌PLFA的变化幅度达到30%以上,革兰氏阳性菌与革兰氏阴性菌的脂肪酸比值升高,而真菌/细菌的比例降低了约70%.这种改变可能进一步影响到土壤中C、N等养分的生物地球化学循环,这有待深入的研究.     

Influences of global environmental changes on arbuscular mycorrhizal fungal communities: a review北大核心CSCD

丛枝菌根(arbuscular mycorrhizal, AM)真菌是生态系统地上地下部的重要连接体,对其群落结构特征的研究有助于菌种资源的发掘和生态系统的可持续发展.人类生产生活活动对全球环境带来了一系列的改变,如二氧化碳和臭氧浓度升高、氮沉降、增温及降水减少/增多等,全球环境变化对AM真菌群落结构的影响也引起了广泛关注.针对二氧化碳和臭氧浓度升高、增温、氮沉降和降水减少/增多等全球环境变化因子,总结其对AM真菌群落结构影响的国内外研究进展,探讨全球环境变化对AM真菌群落的可能作用途径.已有模拟全球环境变化实验研究主要集中于北半球的草原、农田和森林系统.大多研究发现二氧化碳和臭氧浓度升高未对AM真菌多样性产生不利影响,但使AM真菌群落结构显著分异.氮沉降和增温对AM真菌多样性的影响表现为降低、无显著影响和增加等多种情况,对AM真菌群落结构的影响也表现为未显著和显著分异,主要与模拟实验处理方式、增加幅度、土壤养分水平和生态系统类型等因素有关.降水减少未显著影响AM真菌群落结构和多样性,而降水增加使AM真菌群落结构发生显著分异.这些研究主要注重AM真菌群落结构和多样性如何改变等生态现象而潜在机理探索以及热带和南半球不同生态系统下的研究尚不足.另外,鉴于全球变化因子间的关联性,复合因子对AM真菌群落结构的影响值得重视.(图1表4参113)     

两种间作体系对丛枝菌根真菌侵染及多氯联苯去除的影响

多氯联苯(Polychlorinated biphenyls,PCBs)是一类典型的环境有机污染物,植物与微生物的联合修复能够显著提高PCBs的降解率.以丛枝菌根(Arbuscular mycorrhiza,AM)真菌摩西管柄囊霉(Funneliformis mosseae)M47V为供试菌种,温室盆栽条件下设置玉米/黑麦草间作、玉米/紫花苜蓿间作以及玉米单作等3个处理(均接种AM真菌),研究间作对玉米根系AM真菌侵染及土壤中PCBs去除的影响.种植90 d后测定玉米根系AM真菌侵染率、生物量、土壤PCBs含量及同系物组成、16S rDNA基因丰度,并采用末端限制性片段长度多态性(Terminal restriction fragment length polymorphism,T-RFLP)技术分析细菌群落结构.结果显示,间作对玉米根系AM真菌侵染率、玉米生物量和土壤碱解氮含量均有显著促进作用,对土壤细菌丰度和群落结构产生显著影响,其中玉米/紫花苜蓿间作显著提高了土壤细菌数量(P0.05);间作显著提高五氯联苯及总PCBs的降解率,此外玉米/黑麦草间作还显著提高三氯联苯的降解率;土壤PCBs同系物组分与细菌T-RFs片段中128 bp、148 bp片段均具有显著相关性.本研究表明,间作与AM真菌对提高玉米生物量具有协同作用,并通过影响细菌群落结构与丰度促进土壤中多氯联苯的转化与降解,同时改变其同系物结构组成,提高PCBs修复效率.     

氮沉降增加对贝加尔针茅草原土壤微生物群落结构的影响

土壤微生物是草原土壤生态系统的重要组成部分。为研究氮沉降增加对草原土壤微生物群落结构的影响,以内蒙古贝加尔针茅草原为研究对象,开展连续6年(2010—2015年)模拟氮沉降试验,以N计算,设置:N0(0 kg·hm~(-2))、N50(50kg·hm~(-2))、N100(100 kg·hm~(-2))、N150(150 kg·hm~(-2))和N300(300 kg·hm~(-2))5个处理,采用磷脂脂肪酸(PLFA)技术测定0~10 cm土壤特征微生物PLFA生物标记数量并探讨土壤微生物群落结构对氮沉降的响应。结果表明:随氮添加量增大,土壤微生物总PLFAs、细菌PLFAs、革兰氏阳性细菌PLFAs、革兰氏阴性细菌PLFAs和放线菌PLFAs含量呈先升高后降低的趋势,均以N100(100 kg·hm~(-2))处理最高。土壤微生物群落PLFA标记的主成分分析显示,不同氮添加下土壤微生物PLFA标记有显著差异。相关分析表明,土壤革兰氏阳性菌、放线菌PLFA含量、G~+/G~-与土壤p H值呈显著负相关,土壤微生物总PLFAs、土壤细菌PLFAs、革兰氏阳性菌PLFAs、革兰氏阴性菌PLFAs、放线菌PLFAs和饱和脂肪酸PLFAs含量均与土壤速效磷含量呈显著正相关。综合研究表明,连续6年氮添加改变了贝加尔针茅草原土壤微生物群落结构,土壤p H值和土壤速效磷含量是驱动这种变化的主要因素。     

植物根圈微生物群落与功能特异性机制研究

植物-土壤微生物交互作用在土壤养分循环、碳固存和温室气体排放等生态过程中发挥着重要作用,而植物源有机物输入被认为是植物-微生物交互作用的纽带。根圈土壤微生物在群落结构和功能上与根圈外土壤差异显著,并存在一定的植物群落特异性。植物源有机物的高度可利用性对土壤微生物具有复杂的影响,改变着土壤生态过程。因此,揭示植物源有机物的输入对土壤微生物的影响有助于深化对植物-土壤微生物反馈作用的认识,同时为养分循环调控、肥料施用时效、作物增产和温室气体排放及生态平衡维持提供理论支持。基于国内外最新相关研究进展,综述了两大类植物源有机物(根际沉积和凋落物)的组成和输入时间对土壤微生物群落结构和特定功能(以氮循环为例)的影响机制;探讨了稳定性同位素示踪技术、分子探针技术和宏基因组学等研究方法在植物-土壤微生物交互作用中的综合应用;总结了植物生命周期内植物源有机物化学组成和输入时空差异对植物特异性土壤微生物群落的诱导机制。植物源有机物输入对微生物群落结构和功能具有重要影响,不但显著提高优势微生物群落生物量、改变微生物群落结构及相关功能、调控特定土壤微生物活性,并且其化学性质多样性决定了土壤微生物群落植物特异性。因此,植物源有机物输入是驱动植物根圈特异微生物群落结构演替与功能演变的重要因子。     

Changes in microbial community characteristics and soil organic matter with nitrogen additions in two tropical forests

Microbial communities and their associated enzyme activities affect the amount and chemical quality of carbon (C) in soils. Increasing nitrogen (N) deposition, particularly in N-rich tropical forests, is likely to change the composition and behavior of microbial communities and feed back on ecosystem structure and function. This study presents a novel assessment of mechanistic links between microbial responses to N deposition and shifts in soil organic matter (SOM) quality and quantity. We used phospholipid fatty acid (PLFA) analysis and microbial enzyme assays in soils to assess microbial community responses to long-term N additions in two distinct tropical rain forests. We used soil density fractionation and 13C nuclear magnetic resonance (NMR) spectroscopy to measure related changes in SOM pool sizes and chemical quality. Microbial biomass increased in response to N fertilization in both tropical forests and corresponded to declines in pools of low-density SOM. The chemical quality of this soil C pool reflected ecosystem-specific changes in microbial community composition. In the lower-elevation forest, there was an increase in gram-negative bacteria PLFA biomass, and there were significant losses of labile C chemical groups (O-alkyls). In contrast, the upper-elevation tropical forest had an increase in fungal PLFAs with N additions and declines in C groups associated with increased soil C storage (alkyls). The dynamics of microbial enzymatic activities with N addition provided a functional link between changes in microbial community structure and SOM chemistry. Ecosystem-specific changes in microbial community composition are likely to have far-reaching effects on soil carbon storage and cycling. This study indicates that microbial communities in N-rich tropical forests can be sensitive to added N, but we can expect significant variability in how ecosystem structure and function respond to N deposition among tropical forest types.     

Nutrient subsidies to belowground microbes impact aboveground food web interactions

Historically, terrestrial food web theory has been compartmentalized into interactions among aboveground or belowground communities. In this study we took a more synthetic approach to understanding food web interactions by simultaneously examining four trophic levels and investigating how nutrient (nitrogen and carbon) and detrital subsidies impact the ability of the belowground microbial community to alter the abundance of aboveground arthropods (herbivores and predators) associated with the intertidal cord grass Spartina alterniflora. We manipulated carbon, nitrogen, and detrital resources in a field experiment and measured decomposition rate, soil nitrogen pools, plant biomass and quality, herbivore density, and arthropod predator abundance. Because carbon subsidies impact plant growth only indirectly (microbial pathways), whereas nitrogen additions both directly (plant uptake) and indirectly (microbial pathways) impact plant primary productivity, we were able to assess the effect of both belowground soil microbes and nutrient availability on aboveground herbivores and their predators. Herbivore density in the field was suppressed by carbon supplements. Carbon addition altered soil microbial dynamics (net potential ammonification, litter decomposition rate, DON [dissolved organic N] concentration), which limited inorganic soil nitrogen availability and reduced plant size as well as predator abundance. Nitrogen addition enhanced herbivore density by increasing plant size and quality directly by increasing inorganic soil nitrogen pools, and indirectly by enhancing microbial nitrification. Detritus adversely affected aboveground herbivores mainly by promoting predator aggregation. To date, the effects of carbon and nitrogen subsidies on salt marshes have been examined as isolated effects on either the aboveground or the belowground community. Our results emphasize the importance of directly addressing the soil microbial community as a factor that influences aboveground food web structure by affecting plant size and aboveground plant nitrogen.     

Microbial community variation and its relationship with nitrogen mineralization in historically altered forests

Past land use can impart soil legacies that have important implications for ecosystem function. Although these legacies have been linked with microbially mediated processes, little is known about the long-term influence of land use on soil microbial communities themselves. We examined whether historical land use affected soil microbial community composition (lipid profiles) and whether community composition was related to potential net nitrogen (N) mineralization rates in southern Appalachian (USA) forest stands abandoned from agriculture or logging and reforested >50 yr ago. Microbial community composition was determined by a hybrid procedure of phospholipid fatty acid (PLFA) and fatty acid methyl ester (FAME) analysis. We found that community composition varied significantly with past land use. Communities in formerly farmed stands had a higher relative abundance of markers for gram-negative bacteria and a lower abundance of markers for fungi compared with previously logged and reference (i.e., no disturbance history) stands. Potential net N mineralization rates were negatively correlated with fungal and gram-negative bacterial markers in both farmed and reference stands, and fungal abundance and soil bulk density effectively predicted mineralization rates in all stands. Our results indicate that the alteration of microbial communities by historical land use may influence the ecosystem processes they mediate. This is in contrast to typical expectations about microbial community resilience to change. Here, the decrease in fungal abundance observed from disturbance appeared to result in decreased nitrogen mineralization over the long term.     

Consistent effects of nitrogen fertilization on soil bacterial communities in contrasting systems

Ecosystems worldwide are receiving increasing amounts of reactive nitrogen (N) through anthropogenic activities. Although the effects of increased N inputs on plant communities have been reasonably well studied, few comparable studies have examined impacts on whole soil bacterial communities, though they play critical roles in ecosystem functioning. We sampled soils from two long-term ecological research (LTER) experimental N gradients, both of which have been amended with NH4NO3; a grassland at Cedar Creek (27 years of N additions) and an agricultural field at Kellogg Biological Station (8 years of N additions). By examining shifts in bacterial communities across these contrasting ecosystem types, we could test competing hypotheses about the direct and indirect factors that might drive bacterial responses to elevated N inputs. Bacterial community structure was highly responsive to N additions. We observed predictable and consistent changes in the structure of the bacterial communities across both ecosystem types. Our results suggest that bacterial communities across these gradients are more structured by N and/or soil carbon availability than by shifts in the plant community or soil pH associated with the elevated nitrogen inputs. In contrast to the pronounced shifts in bacterial community composition and in direct contrast to the patterns often observed in plant communities, increases in N availability did not have consistent effects on the richness and diversity of soil bacterial communities.     

土壤磷素微生物作用的研究进展

土壤中许多微生物(包括菌根真菌)能够通过产生质子和有机酸溶解土壤不溶态无机磷，通过分泌磷酸酶水解有机磷，但微生物的这种作用受土壤供磷与植物对磷需求间平衡的控制。土壤微生物量中的磷是土壤有机磷最为活跃的部分，由于其周转快、极易矿化为植物有效磷而成为土壤有效磷的活性库。目前，测定土壤微生物量中的磷的方法并不统一，而熏蒸提取法的应用最为广泛。文章阐述了土壤微生物在提高土壤磷素有效性磷中所起的作用，介绍了土壤微生物量中的磷周转及其对土壤磷素有效性调节的重要性，并总结分析了熏蒸提取法测定土壤微生物量中的磷的实用性和局限性。     

Tree species and mycorrhizal associations influence the magnitude of rhizosphere effects

Previous research on the effects of tree species on soil processes has focused primarily on the role of leaf litter inputs. We quantified the extent to which arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) tree species influence soil microbial activity and nutrient availability through rhizosphere effects. Rhizosphere soil, bulk soil, and fine roots were collected from 12 monospecifc plots (six AM and six ECM tree species) planted on a common soil at the Turkey Hill Plantations in Dryden, New York. Rhizosphere effects were estimated by the percentage difference between rhizosphere and bulk soil samples for several assays. Rhizosphere effects on soil microbes and their activities were significant for ECM species but in only a few cases for AM species. In AM tree species, microbial biomass, net N mineralization, and phosphatase enzyme activity in the rhizosphere were 10-12% greater than in bulk soil. In ECM tree species, rhizosphere effects for microbial biomass, C mineralization rates, net N mineralization, and phosphatase activity were 25-30% greater than bulk soil, and significantly greater than AM rhizosphere effects. The magnitude of rhizosphere effects was negatively correlated with the degree of mycorrhizal colonization in AM tree species (r = -0.83) and with fine root biomass (r = -0.88) in ECM tree species, suggesting that different factors influence rhizosphere effects in tree species forming different mycorrhizal associations. Rhizosphere effects on net N mineralization and phosphatase activity were also much greater in soils with pH < 4.3 for both AM and ECM tree species, suggesting that soil pH and its relation to nutrient availability may also influence the magnitude of rhizosphere effects. Our results support the idea that tree roots stimulate nutrient availability in the rhizosphere, and that systematic differences between AM and ECM may result in distinctive rhizosphere effects for C, N, and P cycling between AM and ECM tree species.     

Microbial nitrogen limitation increases decomposition

With anthropogenic nutrient inputs to ecosystems increasing globally, there are long-standing, fundamental questions about the role of nutrients in the decomposition of organic matter. We tested the effects of exogenous nitrogen and phosphorus inputs on litter decomposition across a broad suite of litter and soil types. In one experiment, C mineralization was compared across a wide array of plants individually added to a single soil, while in the second, C mineralization from a single substrate was compared across 50 soils. Counter to basic stoichiometric decomposition theory, low N availability can increase litter decomposition as microbes use labile substrates to acquire N from recalcitrant organic matter. This "microbial nitrogen mining" is consistently suppressed by high soil N supply or substrate N concentrations. There is no evidence for phosphorus mining as P fertilization increases short- and long-term mineralization. These results suggest that basic stoichiometric decomposition theory needs to be revised and ecosystem models restructured accordingly in order to predict ecosystem carbon storage responses to anthropogenic changes in nutrient availability.     

Changes of Soil Enzyme Activities By Simulated Acid and Nitrogen Deposition

Effects of acid and nitrogen depositions on soil microbial activities were studied in a laboratory-based experiment. Five treatments were added to forest soil for five weeks, and soil enzyme activities were determined along with chemical properties. There was little change in pH and nitrogen availability. Dehydrogenase, phosphatase and arylsulphatase activities were decreased by all the acidic treatments compared to the control, while urease activity was increased by the pH 4 treatment. at the same pH treatment, different nitric acid contents induced different urease activities. the results suggest that acid deposition would inhibit microbial activities and that more study is needed to elucidate the impact on nitrogen cycling in forests.     

土壤微生物呼吸热适应性与微生物群落及多样性对全球气候变化响应研究

土壤微生物呼吸热适应性被认为是决定陆地生态系统对全球变暖反馈作用的潜在重要机制,可能显著改变未来的气候变化趋势,然而,土壤微生物群落结构变化如何引起土壤微生物呼吸热适应性的研究目前尚存争议.该文针对气候变化对土壤微生物呼吸的影响研究,梳理了当前对土壤微生物呼吸的热适应性是否存在的争议和不同观点与结论,综述了气候变化对土...