Influence of grass species and soil type on rhizosphere microbial community structure in grassland soils

A number of studies have reported species specific selection of microbial communities in the rhizosphere by plants. It is hypothesised that plants influence microbial community structure in the rhizosphere through rhizodeposition. We examined to what extent the structure of bacterial and fungal communities in the rhizosphere of grasses is determined by the plant species and different soil types. Three grass species were planted in soil from one site, to identify plant-specific influences on rhizosphere microbial communities. To quantify the soil-specific effects on rhizosphere microbial community structure, we planted one grass species (Lolium perenne L.) into soils from three contrasting sites. Rhizosphere, non-rhizosphere (bulk) and control (non-planted) soil samples were collected at regular intervals, to examine the temporal changes in soil microbial communities. Rhizosphere soil samples were collected from both root bases and root tips, to investigate root associated spatial influences. Both fungal and bacterial communities were analysed by terminal restriction fragment length polymorphism (TRFLP). Both bacterial and fungal communities were influenced by the plant growth but there was no evidence for plant species selection of the soil microbial communities in the rhizosphere of the different grass species. For both fungal and bacterial communities, the major determinant of community structure in rhizospheres was soil type. This observation was confirmed by cloning and sequencing analysis of bacterial communities. In control soils, bacterial composition was dominated by Firmicutes and Actinobacteria but in the rhizosphere samples, the majority of bacteria belonged to Proteobacteria and Acidobacteria. Bacterial community compositions of rhizosphere soils from different plants were similar, indicating only a weak influence of plant species on rhizosphere microbial community structure.     

Misidentification of soil bacteria by fatty acid methyl ester (FAME) and BIOLOG analyses

 Fatty acid methyl ester (FAME) analysis is commonly used by soil scientists as a sole method for identifying soil bacteria. We observed discrepancies with this method for identifying certain species of bacteria. Therefore, we used carbon substrate oxidation patterns (BIOLOG) and some simple physical and chemical tests to determine the extent of these discrepancies. Identification with FAME profiles gave false positives for Arthrobacter globiformis, Micrococcus kristinae, and M. luteus, and identification with BIOLOG patterns gave a false positive identification for A. globiformis. A visual check and Gram stain are recommended when FAME analysis identifies soil isolates as M. kristinae or M. luteus, and an additional spore formation test is recommended when FAME and BIOLOG analyses identify isolates as A. globiformis. Received: 14 January 2000     

BIOLOG法测定土壤微生物群的一些局限性

Reduction of Cr(VI)to Cr(Ⅲ）were studied in a fresh wheat rhizosphere soil(Kuroboku,high humicandosol) pretreated with a basal fertilizer consisting of (NH4)2SO4,P2O5 and KH2PO4 and with K2Cr2O7 by using a rhizobox system.It was found that rhizosphere exerted a positive effect on Cr(VI) reduction.Part of the reason was the decrwease of pH in the rhizosphere due to application of (NH4)2SO4,implying that application of physiologically acid fertilizers would reduce Cr(VI) toxicity to plants.     

Importance of DNA quality in comparative soil microbial community structure analyses

This study assessed how different in-situ lysis soil DNA extraction methods influence the DNA yield, quality and hence the results obtained by bacterial and fungal automated ribosomal intergenic spacer analysis (ARISA). Of the methods tested in three soils, a modified hexadecyltrimethylammonium bromide-dithiotreitol (CTAB-DTT)-based method produced ?3 times more DNA of higher quality than the other methods (260/230 nm ratios=1.64–1.82 and 260/280 nm ratios=1.82–1.89 and extracts were less inhibitory of PCR). DNA extracted by this method also yielded more reproducible ARISA ribotypes (89?119 for bacteria and 48?88 for fungi; P<0.05) than DNA extracted by other methods, and consequently produced more reliable estimates of bacterial and fungal diversity in all three test soils. The significant correlations observed between the numbers of reproducible ribotypes and DNA extract 260/230 nm ratios (r=0.88 and 0.72 for bacteria and fungi, respectively; P<0.001) reaffirmed the strong influence of DNA quality on the reliability of microbial diversity indices determined based on PCR-based DNA fingerprinting technique. Results of discriminant function analysis (DFA) and multivariate analysis of variances (MANOVA) performed on ARISA profiles (number and relative abundance of ribotype) revealed that the variability associated with DNA extraction methods did not exceed the biological variability among soil types; this supports the conclusion that high-quality DNA underpins DNA fingerprinting techniques.     

Increased microbial activity and nitrogen mineralization coupled to changes in microbial community structure in the rhizosphere of Bt corn

The interactions between plant roots and soil microorganisms are essential for the function and stability of ecosystems, primary agricultural production and plant health. Despite the importance of soil microbes the response of these microbes to large-scale cultivation of genetically modified (GM) crops is still poorly understood. This study evaluated the potential impact of two lines of transgenic Bt maize on rhizosphere microorganisms. A time-course field experiment was conducted over a period of two years in two fields in Guadalajara (Spain) with monthly sampling from April to September. Rhizosphere soil was collected from transgenic (TG) and unmodified (WT) maize plants from each field and sampling time for the analysis of several important functional and structural soil quality parameters. Total microbial activity, as determined by H³-Thymidine and C¹⁴-Leucine incorporation, was found to be higher in the rhizospheres of the transgenic plants. Similarly, differences in potential ammonification and nitrification were observed in the second year of the study. In contrast, bacterial and fungal microbial catabolic abilities, as determined by Biolog ECO and FF plate analyses, respectively, were more influenced by sampling time than the transgenic nature of the plants. Microbial community structure was also studied by bacterial and phylum-specific PCR-DGGE and PCR cloning approaches. In general, differences were again more pronounced between sampling times, as opposed to between TG versus WT plants, although marked differences were observed within the Betaproteobacteria between plant lines. For the first time it describes the presence of Iamiaceae family in soil, specifically to TG plant rhizosphere. To summarize, the study showed that some important properties of rhizopshere microbes may be impacted by Bt maize cultivation and highlighted the fact that such potential effects need to be viewed within the context of seasonal and spatial variability.     

聚乙烯微塑料对玉米根际土壤微生物群落结构的影响

为了研究聚乙烯类微塑料对玉米根际土壤微生物群落结构的影响,以玉米为试材,以平均分子量为2000、5000、10万的聚乙烯粉末模拟土壤中的微塑料污染,设置5个处理:不添加聚乙烯(CK)、添加分子量为2000(T1)、5000(T2)、10万以上(T3)的聚乙烯且种植玉米、未添加聚乙烯未种植玉米(CK0),分析玉米抽穗期各部位矿质元素代谢和根际土壤微生物群落结构差异。结果显示,矿质元素含量在玉米各部位存在差异,Fe、Cu主要集中在玉米根部, Ca、Mn、Mg在叶中分布最多, K主要集中在茎中;添加不同分子量聚乙烯微塑料后,不同部位的矿质元素较CK增加,且T1处理下增加最多。微生物多样性分析显示,不同分子量聚乙烯微塑料对玉米根际微生物群落组成影响不同。T1处理下除变形杆菌纲、伯克氏菌科细菌丰度增加外,其他细菌丰度较CK均减少;T3处理下,细菌和真菌的丰度较CK都有较大幅度的增加。总体来看,添加聚乙烯后,玉米不同部位矿质元素含量较CK显著增加, 2000分子量聚乙烯能够显著降低土壤中细菌和真菌的丰度, 10万以上分子量聚乙烯使得土壤中细菌和真菌丰度增加,各处理中与环境污染物降解相关的微生物增多。     

Nitrogen transformation and microbial community structure varied in apple rhizosphere and rhizoplane soils under biochar amendment

Journal of Soils and Sediments - Biochar amendment is commonly applied to ameliorate soil environment and alleviate nitrous oxide (N2O) emissions, while our understanding of biochar effects on...     

Subtle changes in rhizosphere microbial community structure in response to increased boron and sodium chloride concentrations

Two of the major constraints to grain production in large areas of South-East Australia and cropping soils worldwide are high levels of subsoil boron (B) and excessive salinity (NaCl). Although the effect of these constraints is often studied in plants, the effect on microbially mediated plant-beneficial processes is unclear. To that end, we investigated the impact of B and NaCl on soil microbial community structure (MCS) in the wheat rhizosphere using BIOLOG ecoplates and terminal restriction fragment length polymorphism (T-RFLP). In addition, the effects of B and NaCl on the nitrogen (N) cycle processes of N fixation and ammonia oxidation were assessed by the construction of clone libraries of diazotrophic (nifH) and ammonia oxidising (amoA) rhizobacteria. Analysis of BIOLOG plates using non-metric multidimensional scaling (MDS) revealed addition of both B and NaCl significantly changed MCS, the latter of which was also significant through the analysis of T-RFLP data. Utilisation of several chemical groups of BIOLOG substrates significantly changed in NaCl-amended soil; both B and NaCl affected utilisation of several individual substrates indicative of plant stress including serine and malic acid. A significant decrease in diversity and species richness was observed in high B rhizosphere soil. The community structure of ammonia-oxidising bacteria (AOB), all of which clustered with Nitrosospira-like sequences, did not significantly change in response to addition of B or NaCl, but addition of the latter resulted in a significant increase of diazotroph clones within the α-proteobacteria similar to Azospirillum sp. It appeared that the addition of B and NaCl to soil changed rhizosphere MCS indirectly through increased soil moisture and subtle changes in root exudate patterns, the addition of the latter producing a more distinct change through increased osmotic pressure, leading to a greater increase in rhizodeposition of nutrients, especially carbohydrates. The implications for the current study are that B and NaCl are more likely to affect rhizosphere MCS indirectly through root exudate quantity and/or quality than directly through microbial toxicity, and that plant health is a major determinant in rhizosphere MCS and normal N cycling.     

Biochemical properties and microbial community structure of five different soils after atrazine addition

Atrazine is one of the most used herbicides worldwide; however, consequences of its long-term agricultural use are still unknown. A laboratory study was performed to examine changes in microbial properties following ethylamino-¹⁵N-atrazine addition, at recommended agronomic dose, to five acidic soils from Galicia (NW Spain) showing different physico-chemical characteristics, as well as atrazine application history. Net N mineralization was observed in all soils, with nitrate being the predominant substance formed. The highest values were detected in soils with low atrazine application history. From 2% to 23% of the atrazine-¹⁵N was found in the soil inorganic-N pool, the highest values being detected after 9 weeks in soils with longer atrazine application history and lower indigenous soil N mineralization. The application of atrazine slightly reduced the amount of soil N mineralized and microbial biomass at short term. Soluble carbohydrates and β-glucosidase and urease activity decreased with incubation time, but were not significantly affected by the single application of atrazine. Microbial community structure changed as consequence of both soil type and incubation time, but no changes in the phospholipid fatty acid (PLFA) pattern were detected due to recent atrazine addition at normal doses. The saturated 17- to 20-carbon fatty acids had higher relative abundance in soils with a longer atrazine history and fungal biomass, as indicated by the PLFA 18:2ω6,9, decreased with the incubation time. The results suggested that the PLFA pattern and soil N dynamics can detect the long-term impact of repeated atrazine application to agricultural soils.     

喀斯特生态系统中乔木和灌木林根际土壤微生物生物量及其多样性的比较

我国喀斯特区域面积分布较广,而喀斯特生态系统的退化已成为当前西南地区面临的严重的生态问题。本研究选取贵州中部两种不同植被类型的生态系统—乔木林和灌木林,以乔木林中的白栎、园果化香和灌木林中的火棘、竹叶椒等主要优势树种为对象,研究不同的植物树种对根际土壤微生物生物量及其细菌群落结构的影响。结果显示:乔木林系统中根际土壤微生物生物量碳、氮显著性高于灌木林,植物的根际效应在乔木林中表现更为显著;同时乔木林中的优势树种通过根系分泌物的作用显著提高根际土壤细菌多样性指数,而灌木林中优势树种的根际土壤微生物量及多样性均未表现出明显的根际效应。因此,植被的演替通过改变土壤微生物的特性影响植物-微生物-土壤之间的物质和能量循环,进一步影响喀斯特生态系统的稳定和健康功能。     

植物促生菌接种对中国芥蓝根际固有微生物群落结构的影响

Plant growth-promoting rhizobacteria (PGPR) have been widely recognized as an important agent,especially as a biofertilizer,in agricultural systems.The objectives of this study were to select efective PGPR for Chinese kale (Brassica oleracea var.alboglabra) cultivation and to investigate the efect of their inoculation on indigenous microbial community structure.The Bacillus sp.SUT1 and Pseudomonas sp.SUT19 were selected for determining the efficiency in promoting Chinese kale growth in both pot and field experiments.In the field experiment,PGPR amended with compost gave the highest yields among all treatments.The Chinese kale growth promotion may be directly afected by PGPR inoculation.The changes of microbial community structure in the rhizosphere of Chinese kale following PGPR inoculation were examined by denaturing gradient gel electrophoresis (DGGE) and principal coordinate analysis.The DGGE fingerprints of 16S rDNA amplified from total community DNA in the rhizosphere confirmed that our isolates were established in the rhizosphere throughout this study.The microbial community structures were slightly diferent among all the treatments,and the major changes depended on stages of plant growth.DNA sequencing of excised DGGE bands showed that the dominant species in microbial community structure in the rhizosphere were not mainly interfered by PGPR,but strongly influenced by plant development.The microbial diversity as revealed by diversity indices was not diferent between the PGPR-inoculated and uninoculated treatments.In addition,the rhizosphere soil had more influence on eubacterial diversity,whereas it did not afect archaebacterial and fungal diversities.     

不同施肥措施对黄芩根际微生物群落结构的影响

探究不同施肥措施对黄芩根际细菌群落结构和种间互作关系的影响,为黄芩的合理施肥和提高土壤微生物多样性提供理论依据。采用高通量测序技术对不施肥(CK)、单施化肥(NPK)、化肥配施生物有机肥(NPKM)3个处理的野外黄芩根际土壤样本细菌多样性、群落结构和网络关系进行测定和分析。结果表明,与CK和NPK处理相比,NPKM处理显著增加了细菌多样性,增幅分别为11.51% 和7.37%。与CK相比,NPK和NPKM处理均显著改变了细菌群落结构。不同处理中,变形菌门是丰度最高的门,其相对丰度均高于28%,此外,CK的优势菌群为寡营养型的酸杆菌门,NPK处理的优势菌群为富营养型的变形菌门和拟杆菌门,NPKM处理的优势菌群为能降解复杂有机物的放线菌门和绿弯菌门。网络分析的结果表明,黄芩根际土壤细菌各物种间的正相关性达64.32%,表明物种间主要呈现出互相合作的关系,与NPK处理相比,CK和NPKM处理的网络节点数分别增加了4.76% 和5.95%,而边数则分别增加了12.13% 和10.54%,说明仅施化肥不利于增强土壤微生物群落之间的联系和系统稳定性。综上所述,施用化肥,特别是化肥配施生物有机肥可以通过增强土壤细菌种间互作联系,优化群落组成,为黄芩生长提供更适宜的环境。     

盐沼湿地中植物根围土壤细菌群落结构和多样性的16S rDNA分析

The structure and diversity of the bacterial communities in rhizosphere soils of native Phragmites australis and Scirpus rnariqueter and alien Spartina alterniflora in the Yangtze River Estuary were investigated by constructing 16S ribosomal DNA （rDNA） clone libraries. The bacterial diversity was quantified by placing the clones into operational taxonomic unit （OTU） groups at the level of sequence similarity of 〉 97%. Phylogenetic analysis of the resulting 398 clone sequences indicated a high diversity of bacteria in the rhizosphere soils of these plants. The members of Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria of the phylum Proteobacteria were the most abundant in rhizobacteria. Chao 1 nonpaxametric diversity estimator coupled with the reciprocal of Simpson＇s index （l/D） was applied to sequence data obtained from each library to evaluate total sequence diversity and quantitatively compare the level of dominance. The results showed that Phragmites, Scirpus, and Spartina rhizosphere soils contained 200, 668, and 382 OTUs, respectively. The bacterial communities in the Spartina and Phragraites rhizosphere soils displayed species dominance revealed by 1/D, whereas the bacterial community in Scirpus rhizosphere soil had uniform distributions of species abundance. Overall, analysis of 16S rDNA clone libraries from the rhizosphere soils indicates that the changes in bacterial composition may occur concomitantly with the shift of species composition in plant communities.     

2-Phenylethylisothiocyanate concentration and microbial community composition in the rhizosphere of canola

Canola crops have been shown to inhibit soil-borne pathogens in following crops. This effect is mainly attributed to the release of low molecular S-containing compounds, such as isothiocyanates, during microbial degradation of the crop residues. We have assessed the effect of low concentrations of phenylethylisothiocyanate (PEITC) on soil microbial communities as well as its rate of degradation in soil and determined the concentration of PEITC and the microbial community structure in the rhizosphere of canola. PEITC was degraded within 96 h by soil microorganisms. PEITC added to the soil daily for 5 d affected both bacterial and eukaryotic community structure, determined by PCR-DGGE. Community structures of bacteria and eukaryotes changed at PEITC concentrations between 1300 and 3790 pmol g⁻¹ soil fresh weight but was unaffected at lower concentrations. The PEITC concentration in the rhizosphere of living canola roots was greater in first order laterals than in second order laterals. The maximal PEITC concentration detected in the rhizosphere was 1827 pmol g⁻¹. Redundancy analysis of the DGGE banding patterns indicated a significant correlation between the PEITC concentration in the rhizosphere and the community structure of the active fraction of eukaryotes and bacteria in the rhizosphere. Other important factors influencing the microbial community structure were soil moisture and plant dry matter. It is concluded that canola may affect the soil microbial community structure not only after incorporation of canola residues but also during active growth of the plants.     

采用Biolog, DGGE 和PLFA三种方法研究利用方式对土壤微生物群落结构的影响

Biolog, 16S rRNA gene denaturing gradient gel electrophoresis （DGGE）, and phospholipid fatty acid （PLFA） analyses were used to assess soil microbial community characteristics in a chronosequence of tea garden systems （8-, 50-, and 90- year-old tea gardens）, an adjacent wasteland, and a 90-year-old forest. Biolog analysis showed that the average well color development （AWCD） of all carbon sources and the functional diversity based on the Shannon index decreased （P 〈 0.05） in the following order： wasteland 〉 forest 〉 tea garden. For the DCCE analysis, the genetic diversity based on the Shannon index was significantly lower in the tea garden soils than in the wasteland. However, compared to the 90-year-old forest, the tea garden soils showed significantly higher genetic diversity. PLFA analysis showed that the ratio of Gram positive bacteria to Cram negative bacteria was significantly higher in the tea garden soils than in the wasteland, and the highest value was found in the 90-year-old forest. Both the fungal PLFA and the ratio of fungi to bacteria were significantly higher in the three tea garden soils than in the wasteland and forest, indicating that fungal PLFA was significantly affected by land-use change. Based on cluster analysis of the soil microbial community structure, all three analytical methods showed that land-use change had a greater effect on soil microbial community structure than tea garden age.     

Plant species influence microbial diversity and carbon allocation in the rhizosphere

Plant species effects on microbial communities are attributed to changes in microbial community composition and biomass, and may depend on plant species specific differences in the quality of resources (carbon) inputs. We examined the idea that plant-soil feedbacks can be explained by a chance effect, which is the probability of a highly productive or keystone plant species is present in the community and will influence the functions more than the number of species per se. A ¹³C pulse labelling technique was applied to three plant species and a species mixture in a greenhouse experiment to examine the carbon flow from plants to soil microbial communities. The ¹³C label was given as CO₂ to shoots of a legume (Lotus corniculatus), a forb (Plantago lanceolata), a grass (Holcus lanatus) and a mixture of the three species. Microbial phospholipid fatty acids (PLFA) was analysed in order to determine the biomass and composition of the soil microbial community. The incorporation of the stable isotope into soil microorganisms was determined through GC-IRMS analyses of the microbial PLFAs. Plant species identity did not influence the microbial biomass when determined as total carbon of microbial phospholipid fatty acids. However, the labelled carbon showed that the grass monoculture (H. lanatus) and the plant mixture allocated more ¹³C into bacteria and actinomycete biomass than the other plant species. H. lanatus monocultures had also the highest amounts of ¹³C allocated to AM-fungi and saprophytic fungi. The carbon allocation from plants to soil microorganisms in a plant species mixture can thus be explained by the presence of a highly productive species that influence soil functions.     

黑土农田施加AM菌剂对大豆根际菌群结构的影响

为揭示在黑土农田条件下施加丛枝菌根(AM)菌剂对作物根际微生物群落的影响,试验以大豆为研究对象,田间播种时分别施加根内球囊霉(Glomus intraradices,GI)和摩西球囊霉(Glomus mosseae,GM)两种AM菌剂,以单施化肥处理(F)和不施加AM菌剂及化肥处理(CK)作为对照,采用传统与现代分子生物学手段,研究大豆根际土壤中菌群结构及根系内AM真菌多样性。结果表明:GI、GM处理的大豆菌根侵染率最高达到78.3%和86.6%;GI、GM、F处理的大豆根际土壤中可培养细菌、真菌和放线菌三大菌群的数量与CK处理相比显著提高(p0.05)。分离大豆结荚期根际土壤中AM真菌孢子,共获得Acaulospora属真菌3种,Glomus属真菌7种,孢子密度均较低,G.intraradices和G.mosseae均为各自处理的优势种群。对大豆结荚期根系和根际土壤PCR-DGGE图谱条带的丰度及优势条带测序分析,结果表明根际土壤中的AM真菌菌群数明显高于根系中AM真菌的菌群数量,GI处理的大豆根际土壤中AM真菌丰度值最大,GM处理大豆根系里的AM真菌丰度值最大,F处理的根际土壤中总AM真菌的数量最少;施加AM菌剂处理的大豆根系及根际土壤中的优势菌群分别为外源施加的两种AM真菌。     

The impact of sugarcane filter cake on the availability of P in the rhizosphere and associated microbial community structure

This study aimed to evaluate the interaction between filter cake (FC), and phosphorus fertilizers with differing solubility on the growth and P nutrition of sugarcane. Effects of soil amendment with FC on different soil P fractions and influence on microbial community structure in the rhizosphere were also assessed. Two glasshouse experiments were conducted with completely randomized block designs. The first experiment evaluated rates of FC using a factorial design (5 × 2): 0, 2.5, 5, 10 and 15 g FC kg^?1 soil applied as either broadcast in bulk soil or in the planting furrow. The second experiment used a factorial design (2 × 3): without and with FC (5 g kg^?1 soil, dry basis), both without P (NP) and with P supplied as either triple superphosphate (TSP) or as rock phosphate (RP), both at the rate of 78.4 mg kg^?1 based on total P. Microbial community structure was determined using TRFLP and dynamics of soil P by Hedley fractionation. Filter cake applied at increasing rates in the absence of P was effective in increasing shoot growth and P uptake by plant, particularly when applied to bulk soil as compared to furrow application. Also, FC improved P uptake and increased the availability of labile inorganic P in the rhizosphere and modified the structure of fungal and bacterial communities, whereas only bacterial and archaea communities were influenced by P fertilizer use. Filter cake was more effective when combined with RP, with increased growth and P utilization and thus can be considered as a feasible and practical option for farmer use in substitution to TSP, a more expensive source.     

Characterization of copper-resistant bacterial community in rhizosphere of highly copper-contaminated soil

The characteristics of copper (Cu)-resistant bacterial communities in a rhizosphere and a non-rhizosphere of the ditch reed, Phragmites, in a highly Cu-contaminated area near a copper mine were investigated. The total Cu concentration was 720 μg·g^–1 in the rhizosphere soil and 5 680 μg·g^–1 in the non-rhizosphere soil. In the rhizosphere, the multiplication of bacteria, particularly non-resistant bacteria, was promoted as compared with the non-rhizosphere. The properties of the bacterial community in the rhizosphere were quite different from those in the non-rhizosphere in terms of Cu sorption ability, growth rate and exopolymer production. Both the Cu-resistant bacteria and non-resistant bacteria in the rhizosphere grew more rapidly in media than those in the non-rhizosphere. For almost all the isolated Cu-resistant bacteria, exopolymer production was prompted by Cu stimuli especially for the isolates from the rhizosphere. The adverse effect of Cu on the growth rate was found to be small for the Cu-resistant bacteria producing exopolymers in a large quantity, suggesting the involvement of exopolymers in the detoxification of Cu. The role of Cu resistance in the bacterial chemotactic migration in the Cu-contaminated soils was not evident.     

不同土壤玉米根际挥发性有机物组成和微生物群落特征

【目的】土壤理化性质和微生物群落的差异显著影响玉米根际挥发性有机物 (volatile organic compounds,VOCs) 的产生和释放。对根际VOCs的深入研究有望为充分挖掘根际生物学潜力和根际调控做出积极贡献。【方法】采集山东德州、河北涞水、河北保定、江西南昌、河南孟津、河南商丘等6个地区的旱地耕层土壤进行为期两个月的玉米盆栽试验,利用顶空固相微萃取联合气相色谱–质谱联用检测技术对根际土壤挥发性有机物进行了分析鉴定,利用实时荧光定量PCR技术对根际细菌和真菌进行了定量分析,利用高通量测序技术对根际细菌16S和真菌ITS进行了测序。【结果】从6个旱地土壤中共检测出44种VOCs,主要是烷烃、烯烃、酯类、胺类、有机酸和芳香类化合物,其中多种化合物与植物或微生物的生长代谢密切相关。胺类化合物N-Benzyl-N-ethyl-p-isopropylbenzamide和D-2-Bromolysergic acid diethylamide在6个土壤中均被检出,占总量的54.2%;其次检出最多的是烷烃和烯烃,占总量的31.1%和7.6%。江西南昌土壤释放的VOCs在数量和丰富度上均显著高于其他土壤,且大部分为烷烃和烯烃类化合物;从河北保定土壤中检出了6种特有的有机酸和酯类化合物。供试6种土壤中,河南商丘和河北保定的细菌数量显著高于其他四个地方。南昌土壤真菌数量显著较高,但其细菌数量、丰富度和多样性均显著低于其他土壤。6种土壤中的主要细菌依次为Thaumarchaeota(奇古菌门)、Actinobacteria(放线菌门)、Proteobacteria(变形菌门)、Chloroflexi(绿弯菌门)、Acidobacteria(酸杆菌门)、Firmicutes(厚壁菌门) 和 Unclassified(未分类门),占总细菌群落的92.1%;主要真菌依次为Ascomycota(子囊菌门)、Basidiomycota(担子菌门) 和 Chytridiomycota(壶菌门),占总真菌群落的98.3%。绿弯菌门仅在南昌土壤中占绝对优势,而南昌土壤中奇古菌门和变形菌门的相对丰度显著比其他地区少;子囊菌门在6种土壤中均为绝对优势真菌门。玉米根际释放的VOCs数量和丰富度与pH、硝态氮、细菌多样性和真菌多样性呈显著负相关 (P < 0.05),与铵态氮和真菌数量呈极显著正相关 (P < 0.01);与主要细菌门中的奇古菌门、变形菌门和酸杆菌门呈显著负相关 (P < 0.05),与绿弯菌门呈极显著正相关 (P < 0.01),但是与主要真菌门相关性不显著。【结论】理化性质不同的玉米根际土壤中,微生物群落结构与组成存在显著差异。pH是影响微生物生长的重要因素,酸性土壤中的真菌数量显著高于中性土壤,但是其细菌数量、微生物群落丰富度和多样性均显著小于中性土壤。VOCs的产生和释放受土壤、微生物和植物等众多因素的影响,土壤有机质含量越高、透气性越好、微生物数量越多时,释放的VOCs越丰富。