Influence of the herbicide glyphosate on soil microbial community structure

The side effects of glyphosate on the soil microflora were monitored by applying a range of glyphosate concentrations (0, 2, 20, and 200 μg g⁻¹ herbicide) to incubated soil samples, and following changes in various microbial groups over 27 days. Bacterial propagule numbers were temporarily enhanced by 20 μg g⁻¹ and 200 μg g⁻¹ glyphosate, while actinomycete and fungal propagule numbers were unaffected by glyphosate. The frequency of three fungal species on organic particles in soil was temporarily enhanced by 200 μg g⁻¹ glyphosate, while one was inhibited. One species was temporily enhanced on mineral particles. However, many of these fungi were inhibited by 200 μg g⁻¹ glyphosate in pure culture. There was little agreement between species responses to glyphosate in incubated soil samples and in pure culture.     

鸡粪有机肥对设施菜地土壤重金属和微生物群落结构的影响

通过田间试验,研究在设施菜地上施用不同剂量的鸡粪有机肥对土壤-植物系统中重金属的累积、重金属有效性和土壤微生物群落结构的影响,进一步探讨土壤微生物群落结构与土壤重金属之间的相关关系。结果表明,与对照相比,施用有机肥可提高小白菜地上部生物量,其中施肥量为60 t/hm²时值最大,增幅为59.92%;小白菜地上部Cd、Cr、Cu、Zn和As含量均大幅增加,但Pb含量无明显变化。土壤重金属Cd、Cr、Cu、Zn和As的全量均随鸡粪有机肥施加量的增加而增大,最高增幅分别为21.30%、21.58%、17.40%、19.40%和17.43%,出现明显的累积现象;施用有机肥均增加了土壤Cd、Cr、Cu、Zn和As的有效态含量,而Pb的全量和有效态含量无显著变化;除重金属Pb外,不同重金属元素全量与有效态含量均显著正相关,其中元素Zn的全量与有效态含量相关性最强。磷脂脂肪酸（PLFA）分析结果表明,土壤中含量较高的PLFA为16：0、18：1ω7c、10Me16：0和18：1ω9c,土壤微生物总PLFA和各类群PLFA含量均呈现M0.5 > M1 > CK > M2 > M4;相关性分析结果表明,土壤Cu、As全量和Cd、Cr、Cu、As有效态含量与微生物总PLFA和各类群PLFA含量均呈现显著负相关关系,其中有效态Cr和Cu含量对微生物群落结构的影响最为显著。     

The combination of Arachis pintoi green manure and natural phosphate improves maize growth,soil microbial community structure and enzymatic activities

Plant and Soil - We investigated the effect of the co-composting of Arachis pintoi (AP) as green manure with different sources of rock phosphate on maize growth and soil properties. Composts were...     

石油污染对土壤微生物群落多样性的影响

土壤中的微生物主要有细菌、放线菌、真菌三大类群,微生物在石油污染的土壤中发挥着维持生态平衡和生物降解的功能。文中以四川省遂宁市射洪县某废弃油井周围不同程度石油污染土壤为供试土壤,首先对各组供试土壤的基本理化性质进行测定分析;然后采用平板菌落计数法测定了供试土壤中三大类微生物数量的变化,结果表明:相比未被污染的对照土壤,石油污染的土壤中细菌、放线菌、真菌数量均减少,并且土壤中可培养微生物的数量与土壤含水量呈正相关;再采用454焦磷酸测序技术对土壤中的细菌群落多样性及变化进行16S rRNA基因分析。在所有供试的4个土壤样品中,共鉴定出不少于23 982个有效读取序列和6 123种微生物,相比于未被污染的对照土壤,石油污染土壤中细菌的种类更加丰富,主要优势门类为酸杆菌门、放线菌门、拟杆菌门、绿弯菌门、浮霉菌门和变形菌门。但不同土壤样品中优势菌群的群落结构有所差异,石油污染的土壤中,酸杆菌门、放线菌门和变形菌门的数量最多,未被石油污染的土壤中,放线菌门、拟杆菌门和变形菌门的数量最多。     

Sheep-urine-induced changes in soil microbial community structure

Soil microbial communities play an important role in nutrient cycling and nutrient availability, especially in unimproved soils. In grazed pastures, sheep urine causes local changes in nutrient concentration which may be a source of heterogeneity in microbial community structure. In the present study, we investigated the effects of synthetic urine on soil microbial community structure, using physiological (community level physiological profiling, CLPP), biochemical (phospholipid fatty acid analysis, PLFA) and molecular (denaturing gradient gel electrophoresis, DGGE) fingerprinting methods. PLFA data suggested that synthetic urine treatment had no significant effect on total microbial (total PLFA), total bacterial or fungal biomass; however, significant changes in microbial community structure were observed with both PLFA and DGGE data. PLFA data suggested that synthetic urine induced a shift towards communities with higher concentrations of branched fatty acids. DGGE banding patterns derived from control and treated soils differed, due to a higher proportion of DNA sequences migrating only to the upper regions of the gel in synthetic urine-treated samples. The shifts in community structure measured by PLFA and DGGE were significantly correlated with one another, suggesting that both datasets reflected the same changes in microbial communities. Synthetic urine treatment preferentially stimulated the use of rhizosphere-C in sole-carbon-source utilisation profiles. The changes caused by synthetic urine addition accounted for only 10-15% of the total variability in community structure, suggesting that overall microbial community structure was reasonably stable and that changes were confined to a small proportion of the communities.     

The effects of mineral fertilizer and organic manure on soil microbial community and diversity

The effects of mineral fertilizer (NPK) and organic manure on phospholipid fatty acid profiles and microbial functional diversity were investigated in a long-term (21-year) fertilizer experiment. The experiment included nine treatments: organic manure (OM), organic manure plus fertilizer NPK (OM + NPK), fertilizer NPK (NPK), fertilizer NP (NP), fertilizer NK (NK), fertilizer N (N), fertilizer P (P), fertilizer K (K), and the control (CK, without fertilization). The original soil was extremely eroded, characterized by low pH and deficiencies of nutrients, particularly N and P. The application of OM and OM + NPK greatly increased crop yields, soil pH, organic C, total N, P and K, available N, P and K content. Crop yields, soil pH, organic C, total N and available N were also clearly increased by the application of mineral NPK fertilizer. The amounts of total PLFAs, bacterial, Gram-negative and actinobacterial PLFAs were highest in the OM + NPK treatment, followed by the OM treatment, whilst least in the N treatment. The amounts of Gram-positive and anaerobic PLFAs were highest in the OM treatment whilst least in the P treatment and the control, respectively. The amounts of aerobic and fungal PLFAs were highest in the NPK treatment whilst least in the N and P treatment, respectively. The average well color development (AWCD) was significantly increased by the application of OM and OM + NPK, and the functional diversity indices including Shannon index (H ^′ ), Simpson index (D) and McIntosh index (U) were also significantly increased by the application of OM and OM + NPK. Principal component analysis (PCA) of PLFA profiles and C source utilization patterns were used to describe changes in microbial biomass and metabolic fingerprints from nine fertilizer treatments. The PLFA profiles from OM, OM + NPK, NP and NPK were significantly different from that of CK, N, P, K and NK, and C source utilization patterns from OM and OM + NPK were clearly different from organic manure deficient treatments (CK, N, P, K, NP, NK 6 and NPK). Stepwise multiple regression analysis showed that total N, available P and soil pH significantly affected PLFA profiles and microbial functional diversity. Our results could provide a better understanding of the importance of organic manure plus balanced fertilization with N, P and K in promoting the soil microbial biomass, activity and diversity and thus enhancing crop growth and production.     

植被对土壤微生物群落结构的影响

研究了不同土壤及覆盖其上的植被与土壤微生物群落结构和多样性的关系．植被使土壤中的微生物种类更丰富,群落多样性更高．表层土壤微生物群落中没有明显的优势种群,种间竞争作用较弱．并介绍了研究土壤微生物群落的分子生物学方法．     

Changes in functional diversity of soil microbial community with addition of antibiotics sulfamethoxazole and chlortetracycline

Potential effects of antibiotics on agricultural soil microflora have recently become increasing concerns with antibiotic-contaminated biosolid now being used in agricultural land. However, changes of soil microbial community function caused by the antibiotic-associated disturbance are less addressed. This paper investigated the changes in microbial functional diversity by spiking sulfamethoxazole (SMX) and chlortetracycline (CTC) in a loam paddy soil and then incubating for 21 days. The dose-effect and time-dependent changes of antibiotic-associated disturbance on soil microbial community were analyzed with the soils sampled at 7 and 21 days using Biolog EcoPlate. At day 7 following treatment, SMX decreased functional diversity of soil microbial community, and the treatment of 100 mg SMX kg?1 dry soil had a significant inhibition of average well color development (AWCD) and Shannon index as compared to the control (p?相似文献   

Soil microbial community responses to antibiotic-contaminated manure under different soil moisture regimes

Sulfadiazine (SDZ) is an antibiotic frequently administered to livestock, and it alters microbial communities when entering soils with animal manure, but understanding the interactions of these effects to the prevailing climatic regime has eluded researchers. A climatic factor that strongly controls microbial activity is soil moisture. Here, we hypothesized that the effects of SDZ on soil microbial communities will be modulated depending on the soil moisture conditions. To test this hypothesis, we performed a 49-day fully controlled climate chamber pot experiments with soil grown with Dactylis glomerata (L.). Manure-amended pots without or with SDZ contamination were incubated under a dynamic moisture regime (DMR) with repeated drying and rewetting changes of >20 % maximum water holding capacity (WHC_max) in comparison to a control moisture regime (CMR) at an average soil moisture of 38 % WHC_max. We then monitored changes in SDZ concentration as well as in the phenotypic phospholipid fatty acid and genotypic 16S rRNA gene fragment patterns of the microbial community after 7, 20, 27, 34, and 49 days of incubation. The results showed that strongly changing water supply made SDZ accessible to mild extraction in the short term. As a result, and despite rather small SDZ effects on community structures, the PLFA-derived microbial biomass was suppressed in the SDZ-contaminated DMR soils relative to the CMR ones, indicating that dynamic moisture changes accelerate the susceptibility of the soil microbial community to antibiotics.     

Influence of arbuscular mycorrhizal mycelial exudates on soil bacterial growth and community structure

Plant root systems colonized by arbuscular mycorrhizal (AM) fungi have previously been shown to influence soil bacterial populations; however, the direct influence of the AM extraradical mycelium itself on bacterial growth and community composition is not well understood. In this study, we investigated the effects of exudates produced by AM extraradical mycelia on the growth and development of an extracted soil bacterial community in vitro. The chemical composition of the mycelial exudates was analysed using proton nuclear magnetic resonance spectrometry. Following the addition of exudates to a bacterial community extracted from soil, bacterial growth and vitality were determined using a bacterial vitality stain and fluorescence microscopy. Changes in community composition were also analysed at various times over the course of 3 days by terminal restriction fragment length polymorphism analysis, in combination with cloning and sequencing of 16S rRNA genes. Mycelial exudates increased bacterial growth and vitality and changed bacterial community composition. Several Gammaproteobacteria, including a taxon within the Enterobacteriaceae, increased in frequency of occurrence in response to AM mycelial exudates. This study is the first attempt to identify carbohydrates from the extraradical mycelium of an AM fungus, and demonstrates the direct effects of mycelial exudates on a soil bacterial community.     

Root controls on soil microbial community structure in forest soils

We assessed microbial community composition as a function of altered above- and belowground inputs to soil in forest ecosystems of Oregon, Pennsylvania, and Hungary as part of a larger Detritus Input and Removal Treatment (DIRT) experiment. DIRT plots, which include root trenching, aboveground litter exclusion, and doubling of litter inputs, have been established in forested ecosystems in the US and Europe that vary with respect to dominant tree species, soil C content, N deposition rate, and soil type. This study used phospholipid fatty-acid (PLFA) analysis to examine changes in the soil microbial community size and composition in the mineral soil (0–10 cm) as a result of the DIRT treatments. At all sites, the PLFA profiles from the plots without roots were significantly different from all other treatments. PLFA analysis showed that the rootless plots generally contained larger quantities of actinomycete biomarkers and lower amounts of fungal biomarkers. At one of the sites in an old-growth coniferous forest, seasonal changes in PLFA profiles were also examined. Seasonal differences in soil microbial community composition were greater than treatment differences. Throughout the year, treatments without roots continued to have a different microbial community composition than the treatments with roots, although the specific PLFA biomarkers responsible for these differences varied by season. These data provide direct evidence that root C inputs exert a large control on microbial community composition in the three forested ecosystems studied.     

耕作方式对潮土土壤团聚体微生物群落结构的影响

为探究不同耕作方式对潮土土壤团聚体微生物群落结构和多样性的影响,采用磷脂脂肪酸(P LFA)法测定了土壤团聚体中微生物群落.试验设置4个耕作处理,分别为旋耕+秸秆还田(RT)、深耕+秸秆还田(DP)、深松+秸秆还田(SS)和免耕+秸秆还田(NT).结果 表明:与RT相比,DP处理显著提高了原状土壤和＞5 mm粒级土壤团...     

培养条件下二氯喹啉酸对土壤微生物群落结构的影响

为探讨除草剂二氯喹啉酸对土壤微生物群落结构的影响,在25℃黑暗培养条件下,采用磷脂脂肪酸法(Phospholipid Fatty Acid,PLFA)分析了二氯喹啉酸(0对照、83.3和166.6μg/kg干土)处理对淹水和不淹水水田土壤微生物群落结构的影响。结果表明,在实验处理的60 d内,不淹水水田土壤在83.3μg/kg二氯喹啉酸处理后对土壤微生物生物总量、细菌生物量及真菌生物量有抑制作用,而166.6μg/kg二氯喹啉酸处理后各生物量指标均显著增加,但是两种浓度处理均使土壤真菌/细菌比值下降,说明二氯喹啉酸处理会使不淹水水田土壤微生物稳定性下降;淹水水田土壤在83.3μg/kg二氯喹啉酸处理下,对土壤微生物生物总量和真菌生物量有促进作用,对细菌生物量有一定的抑制作用,166.6μg/kg二氯喹啉酸处理对土壤微生物生物总量、细菌及真菌生物量均有促进作用,从真菌/细菌比值上看,不同浓度处理与对照无显著差异,说明二氯喹啉酸对淹水生物稳定性无明显干扰。PLFA主成分分析表明,不同浓度处理的两种土壤微生物群落均以含14∶0、15∶0、16∶0和18∶2n6c的微生物为优势种群。     

氯嘧磺隆对土壤微生物群落结构的影响

采用磷脂脂肪酸(PLFA)法研究了黑龙江省苇河地区不同氯嘧磺隆施药历史下土壤微生物群落结构的差异, 并测定了土壤中氯嘧磺隆的残留量.结果表明：不同施药历史下氯嘧磺隆在土壤中的残留量均很低;随着施用氯嘧磺隆年限的增加,土壤微生物的PLFA总量减少, 革兰氏阴性菌/革兰氏阳性菌（GN/GP）和真菌/细菌比降低,土壤微生物的压力指数增加.主成分分析表明,氯嘧磺隆显著改变了大豆田土壤微生物群落结构.     

Influence of soil pollution on the composition of a microbial community

The abundance dynamics and composition of indigenous soil microbial communities were studied in soils polluted with naphthalene, dioctyl phthalate, diesel fuel, and crude oil. DGGE analysis of the 16S rRNA genes amplified from the total soil DNA revealed that the bacterial community of uncontaminated soil was more diverse and included no dominant species. In the soil samples polluted with the crude oil, diesel fuel, or dioctyl phthalate, Pseudomonas became the dominant bacteria since the third day of the experiment. In the soil polluted with naphthalene, two genera of bacteria (Pseudomonas and Paenibacillus) were dominant in population on the third day of the experiment, while on the 21th day of the experiment Arthrobacter became dominant. During the experiment, the average number of indigenous bacterial degraders increased approximately by two orders of magnitude. While the key genes of naphthalene catabolism, nahAc and nahH, were not detected in the pristine soil, they were found in a significant amount on the third day after naphthalene addition. Three degrader strains harboring the plasmids of naphthalene biodegradation (IncP-9 group) were isolated on the third day from the soil polluted with naphthalene. Two of these plasmids, although isolated from various degraders, were shown to be identical.     

Rhizodeposition shapes rhizosphere microbial community structure in organic soil

The aims of the study were to determine group specificity in microbial utilization of root-exudate compounds and whole rhizodeposition; quantify the proportions of carbon acquired by microbial groups from soil organic matter and rhizodeposition, respectively; and assess the importance of root-derived C as a driver of soil microbial community structure. Additions of 13C-labelled root-exudate compounds to organic soil and steady-state labelling of Lolium perenne, coupled to compound-specific isotope ratio mass spectrometry, were used to quantify group-specific microbial utilization of rhizodeposition. Microbial utilization of glucose and fumaric acid was widespread through the microbial community, but glycine was utilized by a narrower range of populations, as indicated by the enrichment of phospholipid fatty acid (PLFA) analysis fractions. In L. perenne rhizospheres, high rates of rhizodeposit utilization by microbial groups showed good correspondence with increased abundance of these groups in the rhizosphere. Although rhizodeposition was not the quantitatively dominant C source for microbes in L. perenne rhizospheres, relative utilization of this C source was an important driver of microbial group abundance in organic soil.     

施用生物质炭和羊粪对宿根连作茶园根际土壤微生物的影响

茶树长期宿根连作会导致土壤酸化严重、土壤营养不平衡、根际土壤微生态结构恶化.研究生物质炭、羊粪对宿根连作茶树生长以及土壤微生物群落结构和功能的影响,探讨其对宿根连作茶树土壤环境的调节效果,可为宿根连作茶园土壤微生态的改善提供理论依据.本研究以宿根连作20年的茶园土壤为对象,利用Biolog技术和磷脂脂肪酸(PLFA)方法,研究施用生物质炭(40 t·hm^-2)和羊粪替代部分化肥对连作茶树产量和品质、土壤化学性质、根际土壤微生物群落功能和结构的影响.结果表明:施用生物质炭、羊粪1年后酸化茶园土壤的p H和土壤养分显著提高,并提高了茶叶产量.与常规施肥相比,施用生物质炭、羊粪替代部分化肥处理显著提高了茶树根际土壤微生物的碳源代谢活性和微生物多样性,对胺类、碳水化合物和聚合物的相对利用有所增加.生物质炭和羊粪处理的根际土壤总PLFA含量分别比常规施肥处理提高了20.9%和47.5%,羊粪处理还显著降低了总饱和/总单一不饱和脂肪酸比例.生物质炭和羊粪可改善茶园土壤酸化状况和土壤肥力,对宿根连作茶树的生长具有促进作用,两种措施均不同程度地增加了土壤微生物的代谢活性和微生物量、提高了多样性指数、改善了微生物群落结构.施用生物质炭和羊粪可作为调节宿根连作茶园根际土壤微生态的有效措施.     

氮添加土壤微生物群落结构影响微生物碳利用效率

尽管近年来中国氮(N)沉降水平逐渐趋于稳定,但中国东南地区N沉降相比于其他地区仍处于较高水平。N沉降对陆地生态系统碳循环过程的影响不容忽视。微生物碳利用效率(CUE)是指微生物将吸收的碳转化为生物量碳的效率,高微生物CUE意味着高土壤有机碳存储潜力。因此,探究N沉降背景下微生物CUE的变化将有助于进一步认识陆地生态系统土壤碳存储的变化。然而,目前关于N沉降下微生物群落结构的变化如何影响微生物CUE鲜有报道。在福建省泉州市戴云山国家级自然保护区的罗浮栲林通过N添加模拟N沉降。实验共包括三个N添加处理：对照(CT,+0 kg hm^-2 a^-1)、低氮(LN,+40 kg hm^-2 a^-1)和高氮(HN,+80 kg hm^-2 a^-1)。测定不同处理土壤基本理化性质、微生物生物量、酶活性和CUE,并使用高通量测序对微生物群落结构和多样性进行测定。结果表明,N添加显著影响微生物CUE,随着N添加水平的增加,CUE逐渐增加;相反,土壤pH、可提取有机碳(EOC)和微...     

土壤微生物群落对枯落物输入的响应

枯落物分解在陆地生态系统物质循环能量流动中起着关键性作用,明确枯落物输入对土壤微生物群落的影响有助于理解土壤微生物生物多样性和陆地生态系统功能的相互关系。本文采用整合分析方法,以中国为研究区域,以不添加枯落物为对照组,探究土壤微生物(真菌、细菌、放线菌)及微生物生物量碳、生物量氮对枯落物输入的响应。结果表明:与不添加枯落物相比,添加枯落物后土壤微生物生物量碳、生物量氮分别显著增加3.9%和4.4%;土壤真菌PLFA、细菌PLFA及总微生物PLFA分别增加4.0%、3.1%和2.4%。枯落物输入对土壤微生物的影响受到气候条件、年降水量、植被类型及土壤酸碱度等因素的显著影响;不同气候类型下,土壤微生物对枯落物输入的响应呈现出亚热带季风气候区>温带季风气候区>温带大陆气候区的趋势,以及随着年降水量的增加呈现出先升高后降低的趋势;不同植被类型下,土壤微生物对枯落物输入的响应呈现出阔叶林>草地≈混交林>针叶林的趋势。     

Changes in the microbial community structure during thermophilic composting of manure as detected by the quinone profile method

Quinone profiles and physico-chemical properties were measured to characterize the microbial community structure during a 14-day thermophilic composting of cattle manure mixed with rice straw as a bulking agent. The change in total quinone content (TQ) and the divergence of quinone (DQ) indicated that the microbial biomass reached a peak followed by a decrease, whereas the microbial community diversity increased continuously during the composting process. The high mole fraction of ubiquinones in the raw materials, and at the beginning of the composting period suggested that fungi and/or Proteobacteria were present. The predominance of MK-7 from days 3 to 7 suggested that Bacillus spp. were the main microbial species. An increase in partially saturated and long-chain menaquinones during the latter composting period indicated that the proliferation of various species of Actinobacteria was occurring. The microbial community structure, as expressed by TQ and DQ, corresponded well to physico-chemical properties such as the C/N ratio, pH, O₂ consumption and compost mass reduction.