Average Well Color Development Research Articles

Effects of alkyl-imidazolium ionic liquid [Omim]Cl on the functional diversity of soil microbial communities.

As low-temperature molten salts, ionic liquids (ILs) were considered to be "green" solvents and have begun to see large-scale applications in the chemical reactions, in separation processes, in electrochemistry studies, etc. In recent years, the toxicity of ILs has started to draw attention. To evaluate the effects of the ionic liquid [Omim]Cl on indigenous microbial community in soil, Biolog-ECO plate method were used with the addition of four different concentrations of [Omim]Cl after four different incubation periods (7, 14, 21, 28 days). The present results showed that the average well color development (AWCD) was strongly activated when the soil was contaminated with [Omim]Cl in the early stages of the incubation. However, the activation effect disappeared with extended incubation time. Therefore, the toxic effects of the alkyl-imidazolium ionic liquid ([Omim]Cl) on the functional diversity of soil microbial communities may be reversible. In addition, the kinetic characteristics of microorganisms that used different categories of carbon sources indicated that phenolic compounds were the main C source in the sample soil.

Biodegradation of Polycyclic Aromatic Hydrocarbons (PAHs) by Trichoderma reesei FS10-C and Effect of Bioaugmentation on an Aged PAH-Contaminated Soil

ABSTRACT The co-metabolism of benzo[a]pyrene (B[a]P) and the capacity of the fungus Trichoderma reesei FS10-C to bioremediate an aged polycyclic aromatic hydrocarbon (PAH)-contaminated soil were investigated. The fungal isolate removed about 54% of B[a]P (20 mg L−1) after 12 days of incubation with glucose (10 g L−1) supplementation as a co-metabolic substrate. Bioaugmented microcosms showed a 25% decrease in total PAH concentrations in soil after 28 days, and the degradation percentages of 3-, 4-, and 5(+6)-ring PAHs were 36%, 35%, and 25%, respectively. In addition, bioaugmented microcosms exhibited higher dehydrogenase (DHA) and fluorescein diacetate hydrolysis (FDAH) activities and increased average well-color development (AWCD), Shannon-Weaver index (H), and Simpson index (D) significantly. Principal component analysis (PCA) also distinguished clear differentiation between treatments, indicating that bioaugmentation restored the microbiological function of the PAH-contaminated soil. The results suggest that bioaugmentation by T. reesei FS10-C might be a promising bioremediation strategy for aged PAH-contaminated soils.

鄱阳湖湿地不同土地利用方式下土壤微生物群落功能多样性

PDF HTML阅读 XML下载 导出引用 引用提醒 鄱阳湖湿地不同土地利用方式下土壤微生物群落功能多样性 DOI: 10.5846/stxb201306121688 作者: 作者单位: 江西省分子生物学与基因工程重点实验室,江西省分子生物学与基因工程重点实验室,江西省分子生物学与基因工程重点实验室,江西省分子生物学与基因工程重点实验室;鄱阳湖环境与资源利用教育部重点实验室,江西省分子生物学与基因工程重点实验室;鄱阳湖环境与资源利用教育部重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(31360127,31260110) Response of soil microbial functional diversity to different land-use types in wetland of Poyang Lake, China Author: Affiliation: Key Laboratory of Molecular Biology and Genetic Engineering in Jiangxi Province,Nanchang University,Key Laboratory of Molecular Biology and Genetic Engineering in Jiangxi Province,Nanchang University,Key Laboratory of Molecular Biology and Genetic Engineering in Jiangxi Province,Nanchang University,Key Laboratory of Molecular Biology and Genetic Engineering in Jiangxi Province,Nanchang University; Key Laboratory of Environment and Resource Utilization of Poyang Lake, Ministry of Education,Key Laboratory of Molecular Biology and Genetic Engineering in Jiangxi Province,Nanchang University; Key Laboratory of Environment and Resource Utilization of Poyang Lake, Ministry of Education Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:于2011年5月分别采集鄱阳湖围垦92、48a和38a的水稻田,退田还湖25a的退耕地以及自然湿地共5个样地的表层土壤,利用Biolog-ECO板技术对土壤微生物群落的单一碳源利用情况进行了测定,并结合群落指数和主成分分析(PCA)对培养72 h土壤微生物群落功能多样性变化进行了分析。结果表明:退耕地和自然湿地土壤微生物群落利用31种碳源的能力较强,来自不同围垦年限的土壤微生物群落利用碳源能力均较弱;且随围垦时间的增长,土壤微生物对碳源的利用能力呈降低的趋势。自然湿地、退耕地与围垦92、38a样地土壤之间存在显著的微生物功能多样性差异;围垦对土壤微生物代谢糖类、羧酸类、氨基酸类物质的影响最为明显。结果提示,围垦改变了湿地土壤微生物群落结构,退田还湖有助于湿地土壤微生物群落结构的恢复。 Abstract:Wetland ecosystem, the transitional region between terrestrial ecosystem and aquatic ecosystem, plays a crucial role in global carbon and nitrogen cycle, flood constraint, runoff regulation, climate improvement, pollution prevention and organismal habitats supply. However, as a consequence of human beings' reclamation and contamination in the past centuries, wetland ecosystems around the world have been destructed and their total area has being declining. Hence, it is urgent to restore wetland ecosystem resources and its ecological function. Microorganisms are one of the predominant participants associated with the function of wetlands. To accomplish wetland restoration scientifically and efficiently, it is indispensable to reveal the responding mechanism of microbial variation due to wetlands' reclamation and restoration. In this study, a series of lands under different utilized types were selected as sampling sites in Nanjishan Wetland National Nature Reserve of Poyang Lake, which located in Jiangxi Province, China. The sites were 38, 48 and 92 year-old reclaimed lands (named RL38, RL48 and RL92, all were paddy fields), 25-year-old retired cropland (RC25) and native wetland (NW). In May 2011, surface soil samples (0-20 cm depth) were collected using earth boring auger in these sampling sites. Biolog-ECO plates were performed to survey the sole-carbon-source utilization of soil microbial communities. Average well colour development (AWCD) of all 31 carbon sources and the 6 kinds of carbon sources were calculated respectively. Microbial community indices calculation and principal components analysis (PCA) were carried out to analyze the variations of functional diversity of soil microbial community in exponential phase. It aimed to preliminarily reveal: 1) the effects of reclamation on the functional diversity of soil microbial community; 2) whether it was efficient at microbial level for wetland restoration by returning farmland to lake wetland. In consequence, 1) the average well colour development (AWCD) of all the soil samples was at a low level during the initial 48 hours. Subsequently, all the AWCDs presented a rapid rising in addition to the 92-year reclaimed land. 2) Generally, the order of AWCD of soil microorganisms was as follows: RC25 > NW > RL38 > RL48 > RL92. Notably, it was significantly higher in retired cropland and native wetland than in reclaimed lands (P<0.01). 3) The AWCD variation of carbohydrates, carboxylic acids and amino acids among sampling sites accorded with the total AWCD of all the 31 sole-carbon sources. 4) According to the microbial functional Richness index and the comprehensive loading scores of PCA, the utilization ability order in exponential phase among sampling sites was RC25 > NW > RL48 > RL38 > RL92. On the first two axes, a total 53.22% variation of functional diversity was explained. The results indicated that 1) the functional diversity of soil microbial community was significantly lower in reclaimed lands than in native wetland and decreased with the extension of reclamation age; 2) soil microorganisms associated with metabolism of carbohydrates, carboxylic acids and amino acids were most apparently affected by reclamation. 3) it was efficient, to some extent, to recover the soil microbial metabolic activity by returning the farmland to lake wetland. 参考文献 相似文献 引证文献

O3浓度升高和太阳辐射减弱对小麦根际土壤微生物功能多样性的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 O3浓度升高和太阳辐射减弱对小麦根际土壤微生物功能多样性的影响 DOI: 10.5846/stxb201308052029 作者: 作者单位: 南京信息工程大学环境科学与工程学院,南京信息工程大学环境科学与工程学院,南京信息工程大学环境科学与工程学院,南京信息工程大学环境科学与工程学院,南京信息工程大学环境科学与工程学院 作者简介: 通讯作者: 中图分类号: 基金项目: 教育部高等学校博士学科点专项科研基金(20123228110003); 国家自然科学基金(41075114) Effects of ozone fumigation and depressed solar irradiance on soil microbial functional diversity in winter wheat rhizosphere Author: Affiliation: Nanjing University of Information Science Technology,Jiangsu Key Laboratory of Atmospheric environmental monitoring and Pollution control high-tech research,Nanjing University of Information Science Technology,Jiangsu Key Laboratory of Atmospheric environmental monitoring and Pollution control high-tech research,Nanjing University of Information Science Technology,Jiangsu Key Laboratory of Atmospheric environmental monitoring and Pollution control high-tech research,Nanjing University of Information Science Technology,Jiangsu Key Laboratory of Atmospheric environmental monitoring and Pollution control high-tech research,Nanjing University of Information Science Technology,Jiangsu Key Laboratory of Atmospheric environmental monitoring and Pollution control high-tech research Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:采用开顶箱(OTC)法和遮光网技术,设置100 nL/L臭氧熏气与3个辐射减弱梯度结合,模拟臭氧浓度升高和太阳辐射减弱的复合大气背景。用BIOLOG生态测试板,采用孔平均颜色变化率法(AWCD)测定冬小麦根际土壤微生物利用不同碳源的能力,计算微生物群落多样性指数,对不同碳源的利用率进行了主成分分析。两年试验结果显示,臭氧熏气与太阳辐射减弱复合作用,降低了土壤微生物对碳源的利用速度和利用总量;除了聚合物以外其它碳源利用率显著降低;对土壤微生物多样性没有直接的影响;对碳源降解的抑制效应大于增强的O3与减弱的太阳辐射两因素各自的单独作用。太阳辐射减弱20%,一定程度上增加了对聚合物类的分解。O3熏气条件下太阳辐射减弱,糖类、胺类代谢变异度较高,受环境影响较大。 Abstract:Enhanced ozone concentration and depressed solar irradiation were simulated by using open-top chambers (OTCs) method and shading net techniques at 100 nL/L ozone fumigation assembling with three different levels of depressed solar irradiance. The effect of enhanced O3 combination with depressed solar irradiance was also studied. Two experiments were performed over two years. The combination of three OTCs with six shaded chambers was set up. Each OTC fed with 100 nL/L ozone. In the shaded chambers, solar irradiance was reduced to different levels of 20%, 40%, 60% respectively. Combined actions of O3 and depressed solar irradiance were tested by shading net above OTCs. Using unshaded OTC and unfed with O3 as controls. OTC fed with 100 nL/L ozone only, and shaded chamber solar irradiance reduced 20% only were applied too. Each chamber was equivalent and repeated three times. Winter wheat was grown to all life stage in OTCs, shading net and their combine chambers. From reviving to mature stages, in OTCs the plants were treated for 8 h (8:00-16:00) every sunny day with O3, in shading chambers covered net all life stage. The ability of winter wheat (Triticumaestivum)rhizosphere microbial to use different carbon sources were measured by applying BIOLOG ECO MicroPlate and Average WelL-Color Development (AWCD). Microbial diversity index and Principal Component Analysis (PCA) were calculated on the utilization of different carbon sources. Each treatment was assayed in triplicate. The data were initially compared by analysis of variance and differences between means were detected using the Duncans Multiple Range Tests. Values of P < 0.05 indicated significance. Quite similar results were obtained during the two years' experiments. The results suggesting that under ozone fumigation and reduced solar irradiance, AWCD was reduced, catabolic ability of single carbon source was declined too. No obvious influence of O3 combined with shading on soil microbial diversity was found. Principal Component Analysis suggested that different forms of carbon source have different sensitivity. The variation degree of carbohydrates' is higher than others. Under ozone fumigation combined with reduced solar irradiance, AWCD and catabolic ability of single carbon sources were lower than enhanced O3 or lower solar irradiance single acting. For soil microbial, two years' results showed that combination effects of ozone fumigation and reduced solar irradiation reduced both rate and total utilization of carbon sources except polymers. However, there was no direct impact on the diversity of soil microbial. For Inhibitory effect on the degradation of carbon, combined effect of enhanced ozone concentration and reduced solar irradiation was greater than each factor functioning alone. 20% reduction of solar radiation increased the decomposition of polymers to some extent. On the conditions of combined O3 fumigation and solar radiation weakened, that makes the metabolism of carbohydrates and amines highly variable, as they are largely affected by the environment. Enhanced O3 and lower solar irradiation have a cooperative action. Reduced solar irradiance is benefit for winter wheat absorbing O3, resulting in a serious injury. 参考文献 相似文献 引证文献

Impact of fluxapyroxad on the microbial community structure and functional diversity in the silty-loam soil

The aim of this work was to assess the effect of applying three different doses of fluxapyroxad on microbial activity, community structure and functional diversity as measured by respiration, microbial biomass C, phospholipid fatty acid (PLFA) and community-level physiological profiles (CLPPs). Our results demonstrated that substrate-induced respiration (on day 15) and microbial biomass C (on days 7 and 15) were inhibited by fluxapyroxad, but stimulation was observed thereafter. In contrast, fluxapyroxad addition increased the basal respiration and metabolic quotients (qCO2) and respiratory quotients (QR). Analysis of the PLFA profiles revealed that the total and bacterial biomass (both Gram-positive bacteria (GP) and Gram-negative bacteria (GN)) were decreased within the initial 15 days, whereas those as well as the GN/GP ratio were increased at days 30 and 60. Fluxapyroxad input decreased the fungi biomass but increased the bacteria/fungi ratio at all incubation time. Moreover, high fluxapyroxad input (75 mg fluxapyroxad kg−1 soil dry weight) increased the microbial stress level. A principal component analysis (PCA) of the PLFAs revealed that fluxapyroxad treatment significantly shifted the microbial community structure, but all of the observed effects were transient. Biolog results showed that average well color development (AWCD) and functional diversity index (H') were increased only on day 60. In addition, the dissipation of fluxapyroxad was slow in soil, and the degradation half-lives varied from 158 to 385 days depending on the concentration tested.

Effects of Long-Term Fertilization on Microbial Diversity in Upland Soils Estimated by Biolog Ecoplate and DGGE

Organic amendment practices can influence diversity and activities of soil microorganisms. There is a need to investigate this impact compared with other types of materials. This study was carried out to evaluate the long term effects of chemical and organic fertilizer on soil microbial community in upland field. During the last 11 years green manure, rice straw compost, rapeseed cake, pig mature compost, NPK, and NPK + pig mature compost were treated in upland soil. Organic fertilizer treatment found with high bacterial colony forming units (CFUs) as compared to chemical and without fertilizer treatment. There was no significant difference in the actinomycetes and fungal population. The average well color development (AWCD) value was the highest in green manure and, the lowest in without fertilizer treatment. Analyses based on the denaturing gradient gel electrophoresis (DGGE) profile showed that rice straw compost and pig mature compost had a similar banding pattern while rapeseed cake, NPK, NPK + pig mature compost and without fertilizer treatment were clustered in another cluster and clearly distinguished from green manure treatment. Bacterial diversity can be highly increased by the application of organic fertilizer while chemical fertilizer had less impact. It can be concluded that green manure had a beneficial impact on soil microbial flora, while, the use of chemical fertilizer could affect the soil bacterial communities adversely.

Isolation and Characterization of Chlorothalonil-Degrading Bacterial Strain H4 and Its Potential for Remediation of Contaminated Soil

A chlorothalonil (CTN)-degrading bacterial strain H4 was isolated in this study from a contaminated soil by continuous enrichment culture to identify its characteristics and to investigate its potential for remediation of CTN in contaminated soil. Based on the morphological, physiological and biochemical tests and 16S rDNA sequence analysis, the strain was identified as Stenotrophomonas sp. After liquid culture for 7 d, 82.2% of CTN was removed by strain H4. The isolate could degrade CTN over a broad range of temperatures and pH values, and the optimum conditions for H4 degradation were pH 7.0 and 30 °C. Reintroduction of the bacteria into artificially contaminated soil resulted in substantial removal of CTN (> 50%) after incubation for 14 d. Soil samples treated by H4 showed significant increases (P < 0.05) in soil dehydrogenase activity, soil polyphenol oxidase activity, average well-color development obtained by the Biolog Eco plateTM assay and Shannon-Weaver index, compared with the control. Strain H4 might be a promising candidate for application in the bioremediation of CTN-contaminated soils.

Influence of transgenic ath-miR399d tomato lines on microbial community and diversity in rhizosphere soil

Transgenic ath-miR399d tomatoes (Solanum lycopersicum L. cv Zhongshu No. 4) have enhanced phosphorus (P) uptake and accumulation in shoots, and have the potential to improve P-use efficiency in agricultural soils. However, the effects of transgenic ath-miR399d tomatoes on soil microbial community and diversity are poorly understood. Soil carbon source utilization patterns and phospholipid fatty acid (PLFA) profiles were evaluated after a 35-d cultivation of transgenic tomato lines C1 and C2 and wild-type tomato at 0, 150 and 300 mg phosphorus pentoxide (P2O5) kg−1 soil. Microbial diversity indices deduced from carbon source utilization patterns were significantly decreased after cultivating transgenic tomato lines compared to wild-type tomato. So were the average well color development (AWCD) for general carbon sources, carbohydrates and amino acids. The AWCD for general carbon sources was increased with P levels, while the microbial diversity indices did not differ significantly among three P levels. The amounts of total, bacterial and Gram-positive bacterial PLFA significantly declined after cultivating transgenic tomato lines. So were Gram-negative bacterial PLFA at 0 and 150 mg P2O5 kg−1 soil. In contrast, the numbers of individual PLFA, the PLFA ratio of fungi:bacteria and Gram-positive bacteria:Gram-negative bacteria were not significantly affected by genotype or P level after the 35-d cultivation of transgenic tomato lines. Principal component analysis (PCA) for both substrate utilization patterns and PLFA profiles showed good separation of soil microbial communities between the transgenic tomato lines and wild-type tomato. Our results suggest that transgenic ath-miR399d tomatoes have transient adverse effects on microbial community and diversity in rhizosphere soil.

Changes in soil microbial community structure and functional diversity in the rhizosphere surrounding mulberry subjected to long-term fertilization

A long-term field experiment was used to evaluate the effects of different fertilizers (OIO, organic inorganic compound fertilizer specially formulated for mulberry; N, N fertilizer only; NPK, N, P and K fertilizer; NF, the control without fertilization) on microbial abundance, community structure and microbial functional diversity. The OIO treatment exhibited the highest bacterial and actinomycete levels, community diversity, Shannon indices and average well color development (AWCD). However, the N treatment resulted in the highest fungi levels. Bacillus sp. were the dominant bacteria in the OIO treatment. The carbohydrate and carboxylic acid utilization by microbes was highest in the OIO treatment, whereas the amino acid utilization was highest in the N treatment. Most microbial parameters were primarily correlated with the soil organic matter content. The principal component analysis of the DGGE profiles suggested that the culture-independent bacterial community was not really affected by the fertilization treatments but was significantly affected by the sampling time. In contrast, the carbon substrate utilization was significantly affected by the fertilization treatments but not by the sampling time. Our findings suggested that the soil microbial activities were significantly changed by long-term fertilization and that more attention should be devoted to seasonal shifts in the microbial community.

Microbial community and functional diversity associated with different aggregate fractions of a paddy soil fertilized with organic manure and/or NPK fertilizer for 20 years

Microbial communities are sensitive to fertilizations, and the response of microbial communities to different fertilization regimes in bulk soils has been studied. However, it is unclear how microbial communities performance in soil aggregates. We determined the composition and functional diversity of the microbial community within different aggregate size fractions of a paddy soil fertilized with organic manure (OM) or/and mineral NPK fertilizer (NPK/NPKO) for 20 years, along with a control (no fertilizer, NoF). Soils were sampled in late December 2010 from a long-term experimental site established from an uncultivated wasteland in 1990. Five aggregate fractions, i.e., large macroaggregates (>2 mm), macroaggregates (1–2 mm), small macroaggregates (0.25–1 mm), microaggregates (0.053–0.25 mm), and non-aggregated silt and clay particles (<0.053 mm), respectively, were obtained by wet sieving. Microbial community composition was estimated based on phospholipid fatty acids (PLFAs) analysis. Microbial functional diversity was evaluated using the community level physiological profile method by Biolog Eco-microplate. The PLFA signature analysis revealed that microbial biomass tended to decrease with decreasing aggregate size. The application of fertilizer significantly increased the microbial biomass of large macroaggregates relative to the NoF treatment, but there was no significant difference among aggregates of the three fertilization treatments. Average well color development (AWCD) as well as all the functional diversity indices was almost highest in large macroaggregates and microaggregates of NoF, OM, and NPK treatments and in microaggregates of NPKO treatment, while all of them were lowest in silt and clay particles. NPKO treatment led to the greatest microbial functional diversity. AWCD values and McIntosh index (U) of most aggregates under the NPK treatment were significantly increased. The OM treatment did not significantly affect microbial functional diversity associated with different aggregate fractions. Aggregate fractions and fertilization significantly affected microbial community composition and functional diversity. Soil organic C and carbon to nitrogen (C/N) ratio dominated microbial community composition and metabolic profile associated with different aggregates, respectively.

Preliminary characterization of microbial functional diversity using sole-C-source utilization profiles in Tremoal do Pedrido mire (Galicia, NW Spain) .

Peatlands are a global carbon sink. It has been estimated that Northern peatlands store 257-342 Gt of carbon. Most carbon is in the form of peat organic matter whose transformation is largely dependent on microbial activity, and this in turn has a major influence on carbon cycling. The presence of two main physico-chemical environments in the peat deposits -the upper, aerobic, acrotelm and the lower, anaerobic catotelm- suggests that there could be differences in both the microbial activity and communities’ composition with depth. In this preliminary study we analyzed the depth variation in microbial community functional diversity using sole–carbon–source utilization profiles, in a raised bog from Galicia (NW Spain). Substrate utilization was quantified by measuring the absorbance at 590 nm of the colour developed by the reduction of the tetrazolium dye contained in each carbon source. Substrates consumption was followed for 10 days and expressed as average well colour development (AWCD) and microbial diversity (Shannon-Wiener index, H). The highest activity (AWCD 1.6-2.0) and microbial diversity (H 3.3) were found at the surface (upper 2 cm) of the peatland. No substrate was used below a depth of 52 cm. Principal components analysis showed three main depth records of degradation: i) substrates (N-compounds, carbohydrates, carboxylic acids) only used at the surface of the peatland, ii) substrates (mostly carboxylic acids) used at the surface and at 46-48 cm, and iii) substrates (N-compounds and polymers) used from the surface to a depth of 48-52 cm. The overall kinetics of substrate utilization showed four patterns: i) asymptotic, ii) exponential (although of low activity), iii) linear, and iv) no reaction over the whole incubation period. Some differences were observed, both in intensity of substrate degradation and total time of reaction, when substrates were grouped according to the results of principal component analysis. These findings suggest a “stratification” of the microbial communities that may be controlled by the varying geochemical conditions (humidity, temperature, acidity, nutrient- and oxygen availability) with depth, and that the acrotelm/catotelm boundary is an effective barrier for oxidative degradation of the organic matter in peatlands.

Soil microbial functional and fungal diversity as influenced by municipal sewage sludge accumulation.

Safe disposal of municipal sewage sludge is a challenging global environmental concern. The aim of this study was to assess the response of soil microbial functional diversity to the accumulation of municipal sewage sludge during landfill storage. Soil samples of a municipal sewage sludge (SS) and from a sewage sludge landfill that was 3 m from a SS landfill (SS3) were analyzed relative to an undisturbed reference soil. Biolog EcoPlatesTM were inoculated with a soil suspension, and the Average Well Color Development (AWCD), Richness (R) and Shannon-Weaver index (H) were calculated to interpret the results. The fungi isolated from the sewage sludge were identified using comparative rDNA sequencing of the LSU D2 region. The MicroSEQ® ID software was used to assess the raw sequence files, perform sequence matching to the MicroSEQ® ID-validated reference database and create Neighbor-Joining trees. Moreover, the genera of fungi isolated from the soil were identified using microscopic methods. Municipal sewage sludge can serve as a habitat for plant pathogens and as a source of pathogen strains for biotechnological applications.

The impact of metal pollution on soil faunal and microbial activity in two grassland ecosystems

In this study the influence of metal pollution on soil functional activity was evaluated by means of Bait lamina and BIOLOG® EcoPlates™ assays. The in situ bait lamina assay investigates the feeding activity of macrofauna, mesofauna and microarthropods while the BIOLOG® EcoPlate™ assay measures the metabolic fingerprint of a selectively extracted microbial community. Both assays proved sensitive enough to reveal changes in the soil community between the plots nearest to and further away from a metal pollution source. Feeding activity (FA) at the less polluted plots reached percentages of 90% while plots nearer to the source of pollution reached percentages as low as 10%. After 2 and 6 days of incubation average well color development (AWCD) and functional richness (R′) were significantly lower at the plots closest to the source of pollution. While the Shannon Wiener diversity index (H′) decreased significantly at sites nearer to the source of pollution after 2 days but not after 6 days of incubation. Arsenic, Cu and Pb correlated significantly and negatively with feeding activity and functional indices while the role of changing environmental factors such as moisture percentage could not be ruled out completely. Compared to the Bait lamina method that is used in situ and which is therefore more affected by site specific variation, the BIOLOG assay, which excludes confounding factors such as low moisture percentage, may be a more reliable assay to measure soil functional activity.

Response of microbial community to a new fungicide fluopyram in the silty-loam agricultural soil

The impacts of fluopyram on a soil microbial community were studied at three application rates: at the recommended field rate (T1, 0.5mg/kg soil), three-fold recommended field rate (T3, 1.5mg/kg soil) and ten-fold recommended field rate (T10, 5mg/kg soil). Soil samples were taken after 7, 15, 30, 45, 60 and 90 days of application to determine the fluopyram residue and microbial properties (i.e., basal respiration, substrate-induced respiration, microbial biomass carbon, microbial community function and structure). The half-lives of the fluopyram at levels of 0.5, 1.5 and 5mg/kg in soil were calculated to be 64.2, 81.5 and 93.6 days, respectively. The results demonstrated that fluopyram treatment (T1, T3 and T10) decreased microbial biomass C but increased the basal respiration, substrate-induced respiration, and ecophysiological indices (qCO2). Average well color development (AWCD) represents the oxidative capacity of soil microorganisms cultivated in the BIOLOG micro-plates and usually indicates the overall microbial metabolic capacity. The BIOLOG results revealed that the AWCD in the soil treated with 1.5 and 5mg/kg fluopyram (T3 and T10) was significantly lower than that of the control during the incubation period. A similar variation in the diversity indices (Simpson index and McIntosh index) was observed. Phospholipid fatty acid (PLFA) analysis revealed that the addition of fluopyram decreased the total amount of PLFAs, bacterial biomass (both Gram-positive (GP) bacteria and Gram-negative (GN)), fungal biomass, the ratios of the GN/GP and fungi/bacteria at all incubation times. Principal component analyses (PCA) suggested that the addition of fluopyram shifted the soil microbial community structure and function. Hence, fluopyram has a harmful effect on overall soil microbial activity, and changed soil microbial community structure and function.

Effects of different control measures on cucumber yield, quality and soil microbial diversity under greenhouse cultivation.

In order to research the effects of different control measures on soil microbial diversity by Biolog, the greenhouse soils of cucumber cultivated in Shouguang City, Shandong Prorince were collected and the relationship between the soils and yield and quality of cucumber was investigated. The results showed that, the average well color development (AWCD) of returning straw to field (RS) was the highest and that of no fertilizer (CK) was the lowest. The activity of microbe was vigorous at the time of cultivation of 72 h and AWCD of treatments ranged from 0.494 to 0.881. AWCD of RS was 1.3 times than that of conventional fertilization (CF) and the difference reached significant level at the moment. However, AWCD of drip irrigation (DI) was lower slightly than that of CF. Soil microbial diversity changed in different treatments.CF had the lowest Shannon index(H)and Substrate evenness(E), but these two indices increased significantly through the application of RS and DI. Principal component analysis showed that carbon utilization by soil microbial communities also changed in different treatments. RS concentrated in the positive direction of the first principal component and the score coefficients ranged from 4.91 to 5.50. Conversely, others concentrated in the negative direction and the score coefficients ranged from-3.26 to-0.18. Compared with CF, cucumber yield and quality of RS and DI treatments had no significant changes. Simpson′s dominance (Ds) and Substrate richness(S)were positively correlated with cucumber yield, Vc and soluble sugar content. Comprehensive consideration, RS was more helpful to improve the soil micro-ecological envrion-ment than DI. Therefore, future research of RS is necessary for sustainable development of installation agriculture.

Microbial response to repeated treatments of manure containing sulfadiazine and chlortetracycline in soil

Substantive addition of antibiotic-contaminated manure to agricultural soil may lead to “persistent” residues of antibiotics and may affect soil health. Therefore, this study examines the effects of repeated manure treatments containing sulfadiazine (SDZ) and chlortetracycline (CTC) residues, both individually and combined, on the functional diversity and structure of soil microbial communities in the soils under laboratory conditions. The average well color development (AWCD), Simpson diversity index (1/D, dominant populations), Shannon-Wiener diversity index (H′, richness), and McIntosh diversity index (U, evenness) in the antibiotics-treated soils decreased in the first 60-day treatment and then gradually recovered or even exceeded the initial level in the unamended soils with increasing treatment frequency. A total of 11 specific bands in temperature gradient gel electrophoresis (TGGE) profiles were observed and sequence analyzed for five repeated treatments, and most of them belonged to the phyla Firmicutes, Actinobacteria, and Proteobacteria. These results indicate that repeated treatments of manure containing SDZ and CTC residues can alter soil microbial community structure, although they have a temporary suppression effect on soil microbial functional diversity.

Ascophyllum extract application can promote plant growth and root yield in carrot associated with increased root-zone soil microbial activity

Alam, M. Z., Braun, G., Norrie, J. and Hodges, D. M. 2014. Ascophyllum extract application can promote plant growth and root yield in carrot associated with increased root-zone soil microbial activity. Can. J. Plant Sci. 94: 337–348. Root growth and soil microbial activity were examined in two cultivars of carrot following treatment with Ascophyllum nodosum marine-plant extract. Field experiments were established in grower-managed fields of Maverick and Pronto carrots during 2010 and 2011. Soluble Ascophyllum extract powder (SAEP) was applied weekly, bi-weekly or tri-weekly at rates of 0 (control), 0.25, 0.50, 0.75 or 1.0 g L−1 over 11 to 13 wk. Results indicate that SAEP treatment increased root yields of Maverick and Pronto by about 20 and 15%, respectively, reduced proportion of smaller roots and improved harvest index (HI). Maximum yield was found at or above 0.50 g L−1 SAEP for Maverick and at 0.75 g L−1 for Pronto. Soil microbial colony counts, respiration and metabolic activity increased following SAEP applications, but varied with SAEP rate and application frequency. Using the Biolog microbial analysis system, maximum average well colour development (AWCD), substrate diversity (H), substrate evenness (E), and substrate richness (S) responses to extract treatment generally showed successive increases at 0.50, 0.75 and 1 g L−1 SAEP at tri-weekly application frequencies. With more frequent applications, rates below 1 g L−1 led to greater microbial growth, respiration and functional activities. Principal component analysis (PCA) showed a strong relationship between carrot growth, soil microbial populations and activity parameters. These results suggest that seaweed extract application can result in an increase in soil microbial activity associated with increased yield in carrots.

Antioxidant capacity in urban soils

The quality of soils in 31 urban green areas in Pisa was assessed in terms their soil antioxidant systems by measuring antioxidant capacity (TEAC) and phenol substances, soil basal respiration, community level physiological profile (CLPP), expressed as average well color development (AWCD), community metabolic diversity (CMD), the Shannon–Weaver index (H), and soil enzyme activities. The urban results were compared to an extra-urban control area (near the S. Rossore-Migliarino-Massaciuccoli Natural Park).The soils of the greenspaces of Pisa city were mostly sandy, subalkaline, lightly calcareous, with a rather high (mean of 3.27±1.24gC100g−1drysoil) and variable (1.32–7.57gC100g−1drysoil) organic matter content.There were little differences in the functional diversity (AWCD) of soil microbial communities. Dehydrogenase, catalase, alkaline phosphatase, β-glucosidase and lipase showed little variability among soils while arylsulphatase, protease and urease activities varied within a fairly wide range of values. Values of the alkali-and water-soluble TEAC of urban soils varied within quite large ranges (2.53–11.45mMg−1soil and 0.11–2.91mMg−1drysoil, respectively) and were generally higher than those of control. TEAC and phenol substances, both in alkaline and water extracts, were closely correlated (r>0.850, P≤0.01) and were also positively correlated with soil organic C, AWCD, CMD and, H. With the exception of dehydrogenase, the soil antioxidant system showed positive correlations with the enzymatic activities and soil basal respiration. The antioxidant system and soil basal respiration can be considered useful indicators of the soil biological status and soil quality in the examined urban soils.

荒坡地种植巨菌草对土壤微生物群落功能多样性及土壤肥力的影响

研究种植于荒坡地、不同生长年限（1、2、3、5a）的巨菌草对土壤微生物群落功能多样性及肥力的影响。结果表明，不同生长年限巨菌草土壤微生物对不同碳源的利用随培养时间延长而增大，培养72-96 h变化最明显，培养144 h后各土壤AWCD值均达到最大值。总体上AWCD 值大小依次为：2年生 > 3年生 > 1年生 > 5年生 > CK，不同生长年限的巨菌草土壤AWCD值均比对照高，且差异显著，2年生AWCD 值最高，其次为3年生，1年生、5年生巨菌草土壤AWCD值差异不显著。对培养96 h土壤微生物利用碳源特性进行主成分分析，31个碳源中提取的与土壤微生物碳源利用相关的主成分8个，其中主成分1至主成分8分别能够解释变量方差的25.39%、18.89%、11.28%、9.31%、6.84%、5.60%、5.26%、4.71%，合计解释变量方差的87.27%；主成分1、主成分2能够区分不同生长年限巨菌草土壤的微生物群落特征，2年生、3年生巨菌草土壤微生物功能多样性与CK相比，差异显著；与主成分1显著相关的碳源主要是糖类，氨基酸，羧酸和多聚物，与主成分2显著相关的碳源主要是氨基酸。不同生长年限的巨菌草的Shannon （<em>H</em>）、均匀度、Brillouin指数均高于CK，且差异显著，2年生与3年生差异不显著，1年生与5年生差异不显著。总体上不同生长年限巨菌草的土壤的pH值、有机质、碱解氮、有效磷、速效钾的含量比对照高，其中3年生巨菌草的土壤有机质含量比对照高98.20%，5年生巨菌草土壤的碱解氮含量比对照高93.2%；除1年生巨菌草外，有机质、碱解氮含量均与对照差异显著。在荒坡地种植巨菌草，可增加土壤微生物群落功能多样性，在一定程度上提高土壤肥力，荒坡地种植巨菌草能产生一定的生态正效应。;Introduced from Africa by Fujian Agriculture and Forestry University in 2005, the Giant Juncao (<em> Pennisetum</em> sp.) had the features of tall, erect, forested with the high annual output of 200-400 t/hm². The crude protein content of the Giant Juncao was 10.8% after growth for 4 weeks, indicating the advantage of developed root system, strong stress resistance and quick growth variety. The Giant Juncao may be used to produce mushroom, fungi forage and forage additives successfully. Now, the Giant Juncao is used to control soil erosion and improve the soil properties. This paper studied the effects of the Giant Juncao on the soil microbial community functional diversity and fertility with different growth years (1, 2, 3 and 5 years) planted in the barren hillside. The results indicated that the utilization of carbon sources by soil microbes increased when culture time prolonged. The most obvious change happened in the culture time of 72-96 h. AWCD (Average Well Color Development) value reached the maximum in the culture time of 144 h. Generally, the order of AWCD value was 2 years> 3 years > 1 year > 5 years> CK. The values of AWCD of the Giant Juncao with different growth year was significantly higher than CK. AWCD was highest when the growth year of the Giant Juncao was 2 years, follow by 3 years. The difference of AWCD between 1 and 5 years was not significant. The principal component in the utilization of carbon source by soil microbes in the growth time of 96 h was analyzed. The results showed that the 8 principal components extracted from 31 carbon source were related to soil microbial carbon source utilization, the 1-8 principal components account for 25.39%, 18.89%, 11.28%, 9.31%, 6.84%, 5.60%, 5.26%, 5.60% of variables variance respectively, and account for 87.27% of the total variables variance. The principal component 1 and 2 could be used to distinguish the characteristics of soil microbial community with different growth years of Giant Juncao. The diversity of soil microbial community of the 2 and 3 years' Giant Juncao was significantly different with CK. The Shannon (<em>H</em>), Evenness and Brillouin indexes of soil microbial community with different growth time of Giant Juncao were significantly higher than CK. The Shannon (<em>H</em>), Evenness and Brillouin indexes of soil microbial community planted with Giant Juncao between 2 and 3 years, 1 and 5 years had no significant differences. Generally, pH value, organic matter, alkali solution nitrogen, effective phosphorus and rapidly-available potassium contents of soil planted with Giant Juncao were higher than CK. The content of organic matter of soil planted with 3 years old Giant Juncao was higher than CK by 98.20%. The content of alkaline hydrolysis nitrogen of soil planted with 5 years old Giant Juncao was higher than CK by 93.2%. The organic matter and alkali solution content of soil planted with 2, 3 and 5 years old Giant Juncao were significantly different to CK. The Giant Juncao planted in barren hillside could enhance soil microbial community functional diversity and improve soil fertility to a certain extent. Planting Giant Juncao in the Barren Hillside had certain positive ecological effect.

Effects of intercropping grasses on soil organic carbon and microbial community functional diversity under Chinese hickory (Carya cathayensis Sarg.) stands

Chinese hickory (Carya cathayensis Sarg.) is a woody nut and oil tree from China. Intensive management including heavy application of chemical fertiliser and long-term application of herbicides has resulted in serious soil loss and degradation. This study aimed to test the hypothesis that intercropping in the soil under Chinese hickory stands may improve soil fertility and microbial community functional diversity. A field experiment consisting of four treatments (clean tillage; intercropping rape (Brassica rapa L.), ryegrass (Lolium perenne L.) or Chinese milk vetch (Astragalus sinicus L.) was conducted to study the effects of intercropping on soil organic carbon (SOC) structure and microbial community functional diversity under C. cathayensis stand, by means of 13C-nuclear magnetic resonance (NMR), and EcoPlates incubated at 25°C. After 4 years of treatment, intercropping increased available nitrogen (N), phosphorus and potassium in the soil by 25.1–54.2, 4.2–6.0 and 0–22.5 mg kg–1, respectively, relative to the clean tillage treatment; intercropping rape, ryegrass and Chinese milk vetch increased SOC, microbial biomass C (MBC), and water-soluble organic C (WOC) by 23.1–24.7, 138.6–159.7 and 56.2–69.5% (P &lt; 0.05), respectively. The structure of SOC was also greatly changed by intercropping treatments. Intercropping increased carbonyl C by 29.9–36.9% (P &lt; 0.05) and decreased alkyl C, O-alkyl C and aromatic C by 10.0–16.4, 18.9–20.9 and 10.5–16.6% (P &lt; 0.05), respectively. Intercropping markedly improved microbial community functional diversity, which is characterised by increases in average well-colour development (AWCD), Shannon index and evenness index. Correlation analysis showed significant positive correlations among microbial biomass N, water-soluble organic N, SOC, WOC, MBC and AWCD (P &lt; 0.05 or P &lt; 0.01). The results demonstrate that sod cultivation is an effective soil management practice that improves soil quality and eliminates detrimental effects of clean tillage in Chinese hickory production.