土壤微生物多样性与地上植被类型关系的研究进展

土壤微生物是生态系统中重要的组成成分,土壤微生物多样性代表着微生物群落的稳定性,对植物的生长发育和群落结构的演替具有重要作用。同时地上植被也影响土壤微生物多样性,地上植被和地下微生物间具协同作用和正负反馈效应的互作机制。探讨植被和土壤微生物多样性之间的互作关系,为植物保护和生态系统的可持续发展研究提供参考。     

土壤微生物多样性与地上植被类型关系的研究进展

土壤微生物是生态系统中重要的组成成分,土壤微生物多样性代表着微生物群落的稳定性,对植物的生长发育和群落结构的演替具有重要作用.同时地上植被也影响土壤微生物多样性,地上植被和地下微生物间具协同作用和正负反馈效应的互作机制.探讨植被和土壤微生物多样性之间的互作关系,为植物保护和生态系统的可持续发展研究提供参考.     

影响土壤微生物活性与群落结构因素研究进展

土壤微生物在陆地生态系统中具有重要作用,是整个陆地生态系统物质循环、能量流动的推动者,与陆地生态系统地稳定性密切相关。本文就影响土壤微生物活性与群落结构因素研究进展作了综述,主要内容有:土壤理化性状对土壤微生物群落结构的影响;土壤微生物之间的相互作用,土壤动物多样性,植物多样性对土壤微生物群落结构的影响;不同的经营管理措施对土壤微生物群落结构的影响。并对今后的发展趋势作了探讨,提出深入研究土壤微生物群落结构与其在陆地生态系统中的功能关系,合理调控土壤微生物群落结构,维护整个陆地生态系统稳定的研究方向。     

根际微生物对植物与土壤交互调控的研究进展

土壤中拥有非常丰富的微生物群落,这些微生物对植物与土壤之间的交互作用起到了非常重要的调节作用,尤其是根际微生物,其中一些重要的功能微生物作为主要的共生功能体参与到植物根系养分转化中。对根际与根际土壤微生物的形成及其与土壤环境、植物根系之间互作关系的最新研究进展进行了综述,这些研究成果均肯定了根际微生物群落和多样性是积极促进植物个体和维持生态系统功能的活跃因子,并展望了今后土壤微生物在多组学、植物功能性状和全球变化方面的研究前景。     

放牧对草地土壤微生物多样性影响研究进展

土壤微生物是草地生态系统重要组成部分,在草原生态系统中物质与能量循环中起着重要作用。土壤微生物多样性对环境变化很敏感,能较早指示生态系统功能变化。本文就放牧对草地植被、土壤理化性质和微生物多样性的影响及土壤微生物研究方法现状进行了总结,最后就对草地土壤微生物多样性研究进行了展望。     

基于BIOLOG指纹解析三种不同森林类型土壤细菌群落功能差异

土壤微生物是生态系统的重要组成部分,直接参与土壤碳氮循环及土壤有机质矿化过程,在生态系统中具有不可替代的作用[1].土壤微生物群落多样性反映了群落总体的动态变化,而微生物对不同碳源的利用能力很大程度上取决于微生物的种类和固有性质,因此分析土壤微生物对不同碳源利用能力能够在一定程度上反映土壤碳源转化和土壤微生物多样性情况.     

植物多样性对土壤微生物的影响

生物多样性强烈地影响生态系统的过程，生态系统过程的变化可导致生物多样性衰减并因素导致生态系统功能衰退，植物种丰度和植物功能多样性对土壤细菌群落的代谢活性和代谢多样性有成正比的影响。土壤细菌的代谢活性和代谢多样性随植物种数量的对数和植物功能组的数量而直线上升，其原因可能是由植被流入土壤的物质和能量的多样性和数量的增加，也可能是由土壤动物区系起作用的土壤微生境的多样性的增加造成的，由于植物多样性的丧失所引起的植物生物量的减少对分解者群落有强烈的影响，微生物生物量将可能减少，因为在大多数陆地生态系统中，有机碳源限制着土壤微生物的活性。     

转基因作物对土壤微生物群落的影响及主要研究策略

土壤生态系统是农业生态系统安全和农业可持续发展的重要载体,也是人类赖以生存的基础。随着基因工程技术的应用和转基因作物大量种植,在带来重大经济效益的同时,也可能会引发一定的生态风险,包括会对农田土壤生态系统尤其是微生物群落结构和功能产生难以预测的复杂影响。目前这些研究方向已成为土壤生物安全的研究热点。本文简要分析了近年来转基因作物对土壤微生物群落的影响,着重介绍了转基因作物种植影响根际土壤微生物群落多样性的研究进展、土壤微生物群落多样性的研究方法及其评估研究的主要策略等。     

退化喀斯特植被恢复对土壤微生物数量及群落功能多样性的影响

采集不同恢复阶段的土壤样品,采用微生物培养法研究了退化喀斯特植被恢复对土壤微生物数量、群落功能多样性的影响。研究结果表明随着退化喀斯特植被的恢复,土壤微生物数量增加,表现为乔木群落阶段灌木群落阶段草本群落阶段裸地阶段。土壤微生物群落代谢功能分析表明:植被恢复往往导致较高的平均颜色变化率、物种丰富度和功能多样性。乔木群落阶段的平均诱导底物利用率最高,明显地与其他3个恢复阶段不同。总之,植被恢复使得土壤微生物数量增加,碳源平均利用率增强。因此,创造了更好的土壤条件更有利于退化喀斯特植被的恢复。     

风沙黄土区排土场不同恢复类型植物群落与土壤种子库特征

风沙黄土区排土场作为一种人造生态系统,自然条件恶劣,土壤贫瘠,植被恢复困难。为了探明有效的人工促进植被恢复措施,采用植被调查与种子库萌发试验相结合的方法,通过研究不同植被类型地上植物群落与土壤种子库特征及二者的关系,探讨了其植被恢复效益及潜力。结果表明:研究区人工植被恢复下地上植物群落中共47种植物,分属16科40属,土壤种子库共14种植物,分属5科13属,其中均以禾本科、菊科、藜科、豆科占主导地位; 灌木植被的地上植被和土壤种子库的物种多样性均表现为最优; 地上植被与土壤种子库密度的变化范围为88.48～495.47株/m²,74.74～1422.91粒/m²,且均在草地类型下最大。土壤种子库和地上植被的相似性普遍较低,相似性系数仅为0.16～0.23。因此,风沙黄土区排土场的植被恢复与重建需要加强保护与管理,可以考虑构建以草灌配置为主的人工植被恢复模式,保障群落的恢复潜力,并提高群落多样性与稳定性,亦可考虑引入外源种子库提升群落恢复的潜力。     

Development of microbial community during primary succession in areas degraded by mining activities

Together with plants, soil microbial communities play an essential role in the development of stable ecosystems on degraded lands, such as postmining spoil heaps. Our study addressed concurrent development of the vegetation and soil fungal and bacterial communities in the course of primary succession in a brown coal mine spoil deposit area in the Czech Republic across a chronosequence spanning 54 years. During succession, the plant communities changed from sparse plants over grassland and shrubland into a forest, becoming substantially more diverse with time. Microbial biomass increased until the 21st year of ecosystem development and later decreased. Although there was a close association between fungi and vegetation, with fungi mirroring the differences in plant community assemblages, the development of the bacterial community was different. The early succession community in the barren nonvegetated soil largely differed from that in the older sites, especially in its high abundance of autotrophic and free‐living N₂‐fixing bacteria. Later in succession, bacterial community changes were minor and reflected the chemical parameters of the soil, including pH, which also showed a minor change with time. Our results show that complex forest ecosystems developed over 54 years on the originally barren soil of the temperate zone and indicate an important role of bacteria in the initial stage of soil development. Although the arrival of vegetation affects substantially fungal as well as bacterial communities, it is mainly fungi that respond to the ongoing development of vegetation.     

不同植被类型对不同土层黑土土壤微生物群落功能多样性的影响

土壤微生物群落功能多样性对评估土壤生态系统稳定性具有重要作用。本文采用Biolog方法,对比研究长期不同植被类型：自然恢复(GL)、农作物(AL)、人工林(FL)及无植被覆盖(BL)对表层(0～15 cm)和亚表层(15～35 cm)土壤微生物群落功能多样性的影响。结果表明：不同土层土壤微生物的平均颜色变化率(AWCD)变化均表现为GL>AL>FL>BL,且0～15 cm土层的AWCD值均高于对应植被15～35 cm土层。GL、AL和FL处理的土壤微生物Shannon指数和McIntosh指数、总的碳源利用能力均显著高于BL处理的,GL处理0～15 cm土层的Shannon指数和McIntosh指数最高,分别为3.38和6.89。在0～15 cm土层AL和FL处理土壤微生物对羧酸类利用相对较高,而GL处理对氨基酸类利用较高;在15～35 cm土层AL和FL处理土壤微生物对氨基酸类利用最高,而GL被对羧酸类利用的最高。通过主成分分析,GL、AL和FL处理在0～15 cm土层土壤微生物的碳源利用方式及代谢功能相似;15～35 cm土层下AL和FL处理的土壤微生物的碳源代谢...     

Bacterial community structure and function change in association with colonizer plants during early primary succession in a glacier forefield

Plants directly interact with the soil microbial community through litter inputs and root exudates, and these interactions may be particularly important in nutrient poor soils that typically characterize early ecosystem development. However, little is known regarding how plant–microbe interactions may actually drive ecosystem processes in early succession, a perspective this study helps to define. We investigated how soil microbial communities develop and interact with the establishment of the first plants in the recently exposed soils of the Mendenhall Glacier forefield near Juneau, AK, USA. We sampled soils from under two different plant species (alder, Alnus sinuata and spruce, Picea sitchensis) and from unvegetated areas; all samples were collected along a single soil transect that had been exposed for 6 years. The presence or absence of vegetation as well as the type of plant (i.e., alder vs. spruce) structured the soil microbial community. Furthermore, asymbiotic nitrogen (N) fixation rates, which were greater in vegetated soils, correlated with differences in bacterial community composition. Although soil microbial community composition varied with vegetation type, soil nutrient and carbon (C) pools did not correlate with bacterial community composition. Moreover, pH did not significantly vary by vegetation type, yet it was the only soil parameter that correlated with bacterial community composition. Vegetation type explained more of the variation in bacterial community composition than pH, suggesting that plant acidification of soils only partly explains the observed shifts in bacterial communities. Plant specific differences in bacterial community structure may also relate to the chemical composition of litter and root exudates. Our research reveals differences in the bacterial community composition of vegetated soils, and how such differences may promote shifts in fundamental biogeochemical processes, such as rates of asymbiotic N fixation, in early stages of primary succession where low N availability may limit bacterial and plant growth and thus constrain ecosystem development. As such, this suggests that plant–soil microbe interactions in themselves may drive processes that shape the trajectory of primary succession.     

黄土高原不同植被群落多样性与土壤有机碳密度关系研究

为了探明黄土高原不同植被群落多样性与土壤有机碳密度关系,在黄土高原纸坊沟小流域选取几种典型的植被群落(刺槐Robinia pseudoacacia、铁杆蒿Artemisia gmelinii、长芒草Stipa bungeana、狼牙刺Sophora davidii和柠条Caragana korshinskii),野外调查了植被多样性,同时室内测定0—100 cm土壤有机碳含量、密度以及相关土壤环境因子。结果显示:(1)不同植被群落多样性指数(Margalef丰富度、Mclntosh均匀度和Shannon-Wiener多样性)表现出相同的变化特征。柠条和刺槐群落差异不显著(p>0.05),二者显著低于其他植物群落(p<0.05),长芒草和狼牙刺群落最高,二者之间差异不显著(p>0.05),显著高于其他植物群落(p<0.05); 不同植物群落Simpson优势度指数呈现出相反的变化趋势,刺槐>柠条>铁杆蒿>狼牙刺>长芒草。(2)不同植物群落土壤全氮含量、微生物量碳、微生物量氮、速效养分(硝态氮、铵态氮、速效磷)大致表现为相同的变化特征,均表现为长芒草和狼牙刺群落高于其他群落,而柠条和刺槐群落土壤养分含量低于其他植物群落,不同植物群落土壤pH值表现出相反的变化特征。(3)在垂直方向,土壤有机碳密度随土层深度的增加而逐渐减小,80—100 cm土层土壤有机碳密度最低(p<0.05),0—20 cm土层土壤有机碳密度最高,表现出明显的“表聚性”,相同土层土壤有机碳密度大致表现为长芒草和狼牙刺群落高于其他植物群落。(4)相关性分析显示,不同植物群落多样性指数与有机碳和有机碳密度呈显著或极显著的正相关。冗余分析显示,土壤pH值和微生物量碳含量是主导植被多样性和土壤有机碳密度重要驱动因子; 双因素分析表明植被类型和土层深度对土壤有机碳含量和密度具有显著的影响(p<0.05)。     

Enzyme activities as a component of soil biodiversity: A review

Soil enzyme activities are the direct expression of the soil community to metabolic requirements and available nutrients. While the diversity of soil organisms is important, the capacity of soil microbial communities to maintain functional diversity of those critical soil processes through disturbance, stress or succession could ultimately be more important to ecosystem productivity and stability than taxonomic diversity. This review examines selected papers containing soil enzyme data that could be used to distinguish enzyme sources and substrate specificity, at scales within and between major nutrient cycles. Developing approaches to assess soil enzyme functional diversity will increase our understanding of the linkages between resource availability, microbial community structure and function, and ecosystem processes.     

Positive relationship between herbaceous layer diversity and the performance of soil biota in a temperate forest

The current decline in biodiversity is particularly pronounced in the herbaceous layer of forest ecosystems. We explored the relationship between a naturally occurring plant diversity gradient in the understory vegetation of a deciduous forest and several above-and belowground ecosystem processes. We show that particularly soil microbial parameters and microarthropod densities are positively correlated with plant species richness. These results confirm recent findings in grassland ecosystems and highlight the intimate interconnectance between the diversity and functioning of above-and belowground compartments. We conclude that irrespective of a potential causal relationship between plant species richness and belowground processes, it is essential to consider the performance of soil biota in order to understand the relationship between herbaceous layer composition and ecosystem function.     

Succession of plant and soil microbial communities with restoration of abandoned land in the Loess Plateau, China

Purpose

There have been a number of studies on the succession of vegetation; however, the succession of soil microbes and the collaborative relationships between microbes and vegetation during land restoration remain poorly understood. The objectives of this study were to characterize soil microbial succession and to explore the collaborative mechanisms between microbes and vegetation during the restoration of abandoned land through quantitative ecology methods.

Materials and methods

The present research was carried out in the succession of a 5-year abandoned land and its conversion to Hippophae rhamnoides shrubs, Larix principis-rupprechtii plantation, and a naturally regenerated forest (mixed forest). Soil bacterial, archaeal and fungal characteristics were tested by real-time quantitative PCR assays and terminal restriction fragment length polymorphism. The richness, diversity, and evenness indices were employed to analyze plant and microbial communities’ structure. The stability of plant and microbial communities was tested using Spearman’s rank correlation. The relationships between the regeneration scenarios and environmental factors were determined through canonical correspondence analysis.

Results and discussion

The aboveground biomass was significantly different among the sites. Soil bacterial, archaeal, and fungal rRNA gene abundances did not increase significantly with increasing soil organic carbon content. There were higher correlation coefficients between plant and total microbial communities on the richness, diversity, and evenness indices and ratios of positive to negative association compared to ones between plant and individual bacteria, archaea, and fungi. Soil bulk density, clay, pH, and litter were the primary significant environmental factors affecting the structure of plant and microbial communities. The positive relationships between plant and soil bacteria, fungi, and total microbe communities, as well as the negative relationships between plant and archaea, were demonstrated.

Conclusions

The results suggested that plants promote the growth of soil bacteria and fungi during the process of community succession on a small scale; however, plants inhibit the growth of soil archaea.     

Relationship between plants and soil microbial communities in fertilized grasslands

The relationship between biodiversity and ecosystem functioning is of major scientific concern today. Few studies though have measured the interactions between soil microorganisms and plant diversity, the purpose of this study was to examine the link between plant diversity and microbial communities in fertilized versus unfertilized grasslands. Experiments were carried out on a permanent grassland in north-eastern France where agricultural practices had remained unchanged for the last 13 years. The experimental design included two plots of 300 m² (fertilized at 120 kg N ha⁻¹ or non-fertilized). Plots were replicated into three equal sub-plots (100 m²). From each sub-plot, six samples of soil and vegetation were taken at three dates during floristic development. At sampling, ground cover of each species was estimated, and total amount of C and N was determined in aboveground and root biomass. Soil samples were analyzed in order to measure the metabolic fingerprints of microorganisms using Biolog^® GN2 microplates. Floristic composition and carbon substrate utilization patterns of rhizobacterial communities were more diversified in unfertilized than fertilized plots. In unfertilized plots, the development of Convolvulus arvensis and two legumes (Trifolium pratense and Trifolium repens) may help maintain observed floristic diversity. Moreover, an inversion of C and N distribution between aboveground and root biomass during the vegetation cycle probably induced a variation of rhizodeposition. This phenomenon could explain the differences of rhizobacterial metabolic fingerprints observed between experimental plots.     

Land-use history has a stronger impact on soil microbial community composition than aboveground vegetation and soil properties

The response of soil microbial communities following changes in land-use is governed by multiple factors. The objectives of this study were to investigate (i) whether soil microbial communities track the changes in aboveground vegetation during succession; and (ii) whether microbial communities return to their native state over time. Two successional gradients with different vegetation were studied at the W. K. Kellogg Biological Station, Michigan. The first gradient comprised a conventionally tilled cropland (CT), mid-succession forest (SF) abandoned from cultivation prior to 1951, and native deciduous forest (DF). The second gradient comprised the CT cropland, early-succession grassland (ES) restored in 1989, and long-term mowed grassland (MG). With succession, the total microbial PLFAs and soil microbial biomass C consistently increased in both gradients. While bacterial rRNA gene diversity remained unchanged, the abundance and composition of many bacterial phyla changed significantly. Moreover, microbial communities in the relatively pristine DF and MG soils were very similar despite major differences in soil properties and vegetation. After >50 years of succession, and despite different vegetation, microbial communities in SF were more similar to those in mature DF than in CT. In contrast, even after 17 years of succession, microbial communities in ES were more similar to CT than endpoint MG despite very different vegetation between CT and ES. This result suggested a lasting impact of cultivation history on the soil microbial community. With conversion of deciduous to conifer forest (CF), there was a significant change in multiple soil properties that correlated with changes in microbial biomass, rRNA gene diversity and community composition. In conclusion, history of land-use was a stronger determinant of the composition of microbial communities than vegetation and soil properties. Further, microbial communities in disturbed soils apparently return to their native state with time.