Study on the toxicity of acid rain to microbiota in soils

With simulated acid rain and acidification, the soils from both Nanning and Liuzhou municipalities, Guangxi Zhuang Nationality Autonomous Region have been studied to determine the counts of azotobacter, bacteria, actinomyces and the activity of urease in soils, and the changes in respiratory intensity of soil so as to identify the toxicity of acidic substances to microbiota and enzyme in such soils. The concept of the critical pH of toxicity has been developed and used to discuss the representation of the concept, the basis on which the soil treated with simulated acid rain can be taken as an object of study, and the criteria for the identification of toxicity. Based on that as mentioned above, it was found that acid rain behaved to have toxicity to the microbiota in soils from Liuzhou other than from Nanning. The findings may be regarded as an objective basis to study the toxicity of acidic substances to microbiota and enzyme in soils in this region.

Simulating Microbial Functional Diversity Dynamics in Agricultural Soils: An Individual Based Modeling Approach

New agricultural soil model approaches based on the microbiome dynamics must be considered as they can contribute to understand microbiological soil processes directly linked to substrate metabolism and the influence of these processes on plant growth. The present work presents an approach to the modelling of the interactions of the soil microbial functional diversity with the plant in terms of functions associated to specific processes of organic Carbon and Nitrogen metabolism. The substrates transformations arising in the organic matter that enters as a part of an agricultural scheme are the base for define this metabolism. As result, it has been possible to simulate a rhizospheric soil based on the concept of complex system dynamics and Individual Based Modeling known too as Agent-Based Modeling in an agricultural management context. The explicit definition of the microbiome functional diversity and the processing of the structural elements Carbon and Nitrogen, allowed representing the functional dynamics of this complex system composed by microorganisms, Carbon, Nitrogen and the plant. The variables that reflect the biology and the adaptation to the rhizospheric environment characterized the microorganisms and the assemblage community patterns in time. The main simulations output are system glucose and nitrate levels and an approach to plant growth, all resultant from the metabolic process of the considered Carbon and Nitrogen consortia. The results indicate that the microorganism’s diversity assemblages and its functional expression have a fundamental role in terms of plant growth.

Algae and Cyanobacteria in Soils of Moscow

Algal-cyanobacterial communities, soil nano- and microfauna, and mycelium of micromycetes were studied in soils of an administrative district of Moscow. To characterize the habitat conditions of microbiota in the soils of different functional zones of the city, the acid-base conditions and the contents of exchangeable and water-soluble nitrogen, mobile heavy metals, and soluble salts were determined. The diversity of species of algal-cyanobacterial communities, the composition of the dominant species, the proportions of different ecological groups of diatom algae, the diversity of soil nano- and microfauna, and the abundance of colorless and colored mycelium in the urban soils were characterized. The analysis of these parameters showed that the degree of technogenic impact on soil microbiota decreases in the following sequence of functional zones of the city: industrial > traffic > residential > recreation.

西藏湿生扁蕾根际土壤微生物群落结构特征分析

【目的】探究西藏不同产地湿生扁蕾根际土壤微生物群落组成特征,揭示根际土壤核心微生物菌群与根际土壤微生物群落的相互作用,以及影响微生物群落组成的环境因素。【方法】采用Illumina MiSeq高通量测序技术和生物信息学方法对西藏林芝市巴宜区(BY)、察隅县(CY)和工布江达县(GB)湿生扁蕾根际土壤微生物群落组成,及其与土壤理化因子间的相关性进行分析。【结果】湿生扁蕾根际土壤共获得4738个细菌OTUs和3600个真菌OTUs,BY样品根际土壤细菌和真菌丰富度指数最高,CY样品根际土壤细菌和真菌多样性指数最高;不同产地湿生扁蕾根际土壤细菌和真菌群落结构组成存在差异;根际土壤核心细菌菌群有322个属,核心真菌菌群有175个属;根际土壤细菌和真菌互作网络均具有模块化结构且以协同作用为主,核心微生物菌群相对分散,变形菌门、放线菌门、子囊菌门和担子菌门是根际土壤微生物的关键类群;相关性分析表明,核心微生物菌群的改变与土壤理化因子间存在不同程度的相关性;pH、总钾、总磷、总氮、速效钾和速效氮含量与根际土壤微生物群落结构组成显著正相关,总钾、总磷和总氮是影响根际土壤微生物α多样性的关键因子。【结论】不同产地湿生扁蕾根际土壤细菌和真菌群落组成及多样性存在一定的差异,根际土壤微生物菌群的改变与土壤理化因子间存在不同程度的相关性。本研究为湿生扁蕾人工种植及益生微生物菌群的筛选提供了理论依据。

(微)塑料污染对土壤生态系统的影响:进展与思考

塑料已经成为现代社会不可或缺的产品而被广泛应用,塑料污染也成了一个全球性的环境污染问题。近年来,土壤塑料污染的问题也开始受到关注。本文针对近几年来国内外关于塑料污染对土壤生态系统的影响进行综述,主要包括以下几个方面:(1)微塑料对土壤物理化学性质的影响;(2)微塑料对土壤微生物群落的影响;(3)微塑料与土壤动物的相互作用。最后,本文对未来关于土壤微塑料研究的重点方向进行了展望。

川西北退化草地土壤微生物数量与区系研究

通过对三种不同程度退化草地土壤微生物区系和数量的比较分析研究，结果表明不同程度的退化草地在土壤微生物种类与组成、优势菌群与数量等方面有较大差异，种类与数量有随退化程度增高而减少的趋势；三种退化草地土壤微生物数量以细菌占绝对优势，真菌和放线菌较少，并有明显的垂直分布和季节变动规律。

退化草地土壤农化性状与微生物区系研究

通过对三种退化程度不同的草地土壤农化性状与微生物区系进行研究，结果表明，草地退化后，其土壤肥力水平、土壤微生物数量和微生物种类有随退化程度增高而下降（减少）的趋势；退化草地存在不同程度的营养元素比例失调，表现为少氮、缺磷、富钾和高有机质含量，且退化程度接近的草地间，在土壤微生物区系和农化性状有部分类似的特征。

放牧对草原土壤微生物影响研究进展

微生物是草原生态系统不可缺少的成员,对草原生态系统中物质转化、能量流动起着重要作用。笔者就不同放牧强度对草地土壤微生物区系组成、微生物分布格局以及土壤微生物生物量影响的研究现状进行了总结,最后就今后草原土壤微生物研究的侧重点进行了展望。

杨树不同栽培模式生长量、土壤微生物及酶活性的研究

The poplar increment with different cultivation models and the microbiota and enzyme activity were studied based on 7-years’ continuous observation at two stages (1992～1995 and 1996～2000). The poplar stand located in Minquan County of Henan Province with an area of 3.12 hectares. The results showed that the annual average increment in the second stage of all models was higher compared with that in the first stage in height and diameter breast-high (DBH) . The model A and B of the second stage were the best with an increase of 135%, 175% and 214%, 250% higher than that of the first stage, while the control was only 122% and 130%. The amount of three soil microbiota in the second stage was higher than that in the first stage. The bacterium was the most among the three microbiota, and the fungus was the least. All the enzyme activities of five models in the second stage were higher than that in the first stage (except D, E of catalase). The increase ranges from 3% to 161%. In model A and B, the phosphates and urease increased by 135%, 89% and 161%, 105% respectively.

Biochar-based organic fertilizer application rates for Tetrastigma hemsleyanum planted under Moso bamboo

The under-forest economy has received increased attention in China.However,little is known about the effects of co-composted biochar on soil and plant biomass in under-forest planting systems.In this study,plant biomass,soil nutrient levels,and bacterial communities were evaluated after application of biochar-based organic fertilizer(BOF,derived from co-composted biochar-compost)at varying rates to soils supporting Tetrastigma hemsleyanum Diels&Gilg planted under a Moso bamboo(Phyllostachys edulis)forest.BOF treatment increased the biomass of T.hemsleyanum.Compared with the control,BOF application significantly increased soil pH and organic carbon(SOC).The high-throughput sequencing results showed significant differences in the Bacteroidetes,Verrucomicrobia,Chlorofexi,and OD1 phyla among all groups.At the genus level,the control group was characterized by a preponderance of Conexibacter.Rhodanobacter was enriched in soils with a 3%BOF application and Steroidobacter and Spirochaeta were the most prominent phyla in the 5%BOF group.There was no biomarker selected in the 1%BOF group at the genus level.In conclusion,BOF application increased the biomass of T.hemsleyanum when intercropped under a Moso bamboo forest;this effect may be due to changes in the soil physicochemical properties and microbial communities after BOF application.

污泥复混肥对土壤微生物区系影响的研究

对旱地和水田的施用试验结果表明 ,施用污泥复混肥与等量化肥相比 ,在本试验的施肥水平下 ,对硝化细菌和好气性纤维素分解细菌的繁衍具有明显的促进作用 ;对好气细菌、真菌、放线菌和氨化细菌不但没有不良影响 ,反而稍有促进作用 。

4种蚯蚓肠道微生物对砷毒性的响应差异研究

蚯蚓肠道是微生物多样性的一个潜在存储库。砷对蚯蚓肠道微生物群落的影响已被证实,但砷在不同蚯蚓肠道菌群中生物转化的差异仍不清楚。为了进一步阐述土壤中广泛存在的低浓度砷(浓度为5,15,25 mg/kg)对不同种类蚯蚓肠道微生物影响的差异,将4种典型蚯蚓暴露于砷污染土壤后,测定其肠道微生物组成变化,并分析砷对不同蚯蚓肠道内砷富集、形态和砷生物转化基因的影响。结果显示,所有蚯蚓组织内均存在明显的砷富集,其富集系数由高到低依次为:安德爱胜蚓(1.93)>加州腔蚓(0.80)>通俗腔蚓(0.78)>湖北远盲蚓(0.52),蚯蚓组织和肠道内砷形态主要以无机砷为主,其中As(Ⅲ)含量比例>80%,部分蚯蚓组织内还发现少量有机砷。4种蚯蚓肠道微生物群落在门水平上主要以变形菌、厚壁菌和放线菌为主,并与周围土壤细菌群落组成存在显著差异。同时,在土壤和肠道内共检测到17个砷转化基因,其中蚯蚓肠道内As(V)还原和砷转运相关基因相对丰度较高,而砷(去)甲基化基因丰度较低。此外,低浓度砷污染对蚯蚓生长无显著影响,却能引起蚯蚓肠道微生物群落的紊乱。蚯蚓种类和砷污染是引起蚯蚓肠道微生物群落组成变化的主要因素。综上,蚯蚓肠道是一个微生物介导的砷生物转化的重要热区,本研究拓展了我们对土壤动物肠道内砷生物地球化学行为的认知。

冰川棘豆(Oxytropis glacialis)根系土壤细菌多样性特征

冰川棘豆是青藏高原高寒草原和荒漠草原主要伴生毒草之一,对青藏高原草地退化及畜牧业的发展产生严重影响。对4种不同生态环境中冰川棘豆根系土壤细菌的16S rRNA进行高通量测序及生物信息学分析,结合土壤的理化性质,分析了不同生态环境下冰川棘豆根系土壤细菌群落多样性及其与土壤理化因子的关系,探讨了根系土壤细菌对冰川棘豆在高寒生态系统中形成优势种可能的影响。结果表明,在不同生态环境下冰川棘豆根系土壤细菌多样性丰富,且受土壤pH和有机物影响最大,同时,能够保持稳定的核心菌群网络,对冰川棘豆在高寒生态系统中形成优势种具有促进作用。

土壤微生物研究在农田质量评价中的应用

农田生产能力的可持续发展,是当前农田质量评价的主要目标之一。随着土壤微生物学研究的逐渐成熟,可考虑通过微生物角度对农田质量进行分析,以期从土壤微观机理解释农田发展的可持续性。基于文献汇总、统计学分析及对土壤微生物研究的认知,阐述了微生物群落如何反馈农田土壤质量,如对农田管理、作物产量以及土壤污染的反馈功能,并提出了可纳入农田质量评价系统的微生物学指标及相应的测定方法。根据统计学显著性检验方法,综合最小数据集法、土壤质量指数、内梅罗指数等农田土壤质量评价方法,提出农田质量评价的路径流程,以及土样采集与数据分析的具体方案。综上可知,利用土壤微生物指标构建的评价体系,能够更直观反映出农田整治改良项目对耕地造成的影响及收益状况。

Contrasting plant growth performance of invasive polyploid and native diploid Prosopis is mediated by the soil bacterial community

Background Soil microbial communities affect above-ground plant diversity and community composition by influencing plant growth performance.Several studies have tested the effect of soil bacterial microbiome on growth performance of native and invasive plants,but the influence of specific bacterial isolates has not been investigated.Here,we investigated the effects of soil bacterial exclusion by soil sterilization and by inoculation of Streptomyces rhizobacterial isolates on the growth performance of native and invasive Prosopis congeners.Results Plant growth performance of invasive P.juliflora was significantly reduced when grown in sterilized soils,whereas native P.cineraria showed enhanced growth performance in the sterilized soils.When grown in the soil inoculated with the specific Streptomyces isolate from P.juliflora(PJ1),the growth performance of invasive P.juliflora was significantly enhanced while that of native P.cineraria seedlings was significantly reduced.However,inoculation of P.cineraria and P.juliflora seedlings with Streptomyces isolate from the rhizosphere of native P.cineraria(PC1)had no significant effect on the growth performances either of P.juliflora or P.cineraria.Conclusion Our study reveals that invasive P.juliflora experiences positive feedback from the non-native soil bacterial community,while the native P.cineraria experiences negative feedback from its soil bacterial community.Our results provide fresh experimental evidence for the enemy release hypothesis,and further our understanding of the contrasting growth-promoting effects of differentially recruited microbial species belonging to the same genus(Streptomyces)in the rhizospheres of alien invasive and native plants.

Soil bacterial communities under slash and burn in Mozambique as revealed by a metataxonomic approach

The slash-and-burn system is a subsistence agronomical practice widespread in tropical areas worldwide.This system has been extensively studied,especially for its impacts on agronomical aspects and soil physicochemical properties;however,knowledge of soil microbial diversity under slash and bum is scarce.In this study,for the first time,soil bacterial diversity of three locations from Central Mozambique,where slash and burn has been practiced for different durations of the forest fallow period(ca.25,35,and 50 years),was elucidated through a metataxonomic approach.Bacterial communities were evaluated in the genetic horizons of soils under charcoal kilns,crop fields,and forests.The aim of this study was to examine the influence of spatial(location and land use),temporal(forest fallow period),and vertical(horizon)variations on bacterial community structure in relation to soil physicochemical properties.Metataxonomic analysis detected 25 different phyla whose distribution varied horizontally and vertically in relation to soil properties(i.e.,p H,easily oxidizable organic carbon,total nitrogen,and available phosphorus),as well as particle size distribution and mineralogical composition.Such properties were strongly affected and altered by land-use management;in particular,charcoal kilns exhibited better soil properties and greater differences in bacterial community than crop fields and forests,which were quite similar.This might suggest the inability of a forest fallow period shorter than 50 years to improve soil fertility and induce changes in bacterial community.The uncommon application of the pedological approach for microbial evaluation facilitated the detection of a clear separation in bacterial composition along the soil profile,with eutrophic bacteria mainly located in the A horizon whereas oligotrophic bacteria were found in the Bo horizon.These horizontal and vertical heterogeneities in the same study represent a novelty for bacterial metataxonomic analysis.

利用方式对贝加尔针茅草原土壤微生物群落结构与土壤酶活性的影响

土壤微生物和土壤酶活性是影响土壤生态系统物质循环和能量流动的主要驱动力。研究3种利用方式(围封、放牧和刈割)对贝加尔针茅草原土壤微生物群落结构与土壤酶活性的影响,为探索草原可持续利用提供基础数据。结果表明:围封、放牧和刈割利用下土壤微生物PLFA总量分别为30.24nmol/g、16.22nmol/g和14.52nmol/g,且均呈显著差异。0~30cm土层,土壤蔗糖酶活性表现为围封>放牧>刈割;土壤脲酶和碱性磷酸酶活性均表现为刈割>围封>放牧,土壤过氧化氢酶活性在不同利用方式间没有显著差异。土壤微生物PLFA总量与土壤脲酶、蔗糖酶、碱性磷酸酶活性以及pH值、有机碳、全氮、微生物量碳均呈极显著或显著的相关关系。刈割会增加土壤脲酶和碱性磷酸酶活性,但土壤微生物PLFA总量最低;围封相对于放牧有利于增加土壤酶活性和土壤微生物群落结构。综合比较,围封更有利于遏制贝加尔针茅草原的退化。

肠道微生物对土壤中铜、锌、锰生物可给性的影响

为了更全面、准确地评价土壤中金属元素对人体的健康风险,研究土壤中金属元素在结肠阶段的生物可给性具有重要意义。通过采集我国一些地区的6种土壤,利用in vitro方法(PBET和SHIME联用)研究土壤中Cu、Zn、Mn在胃、小肠、结肠阶段的生物可给性。研究显示,土壤中Cu、Zn、Mn在胃阶段的生物可给性分别为23.8%~63.0%、21.2%~64.4%、11.7%~35.6%;从胃阶段到小肠阶段,土壤中Cu的生物可给性提高了0.4%~14.4%,而土壤中Zn在小肠阶段的生物可给性降低了6.7%~38.7%。结肠阶段,土壤中Cu、Zn、Mn的生物可给性分别为2.4%~12.9%、5.7%~18.7%、6.2%~18.9%,与小肠阶段相比,分别降低了21.7%~56.9%、0.4%~36.8%、4.5%~19.1%。结果表明,在肠道微生物存在的情况下,土壤中Cu、Zn、Mn在结肠阶段有较低的人体健康风险。

植物入侵对土壤微生物的影响

入侵植物通过影响入侵地土壤微生物生物量、微生物群落多样性及功能菌群等造成环境威胁,危害生态、经济和社会安全。植物入侵已成为全球性问题,也是当前的研究热点之一。综述了国内外植物入侵影响土壤微生物的研究进展,总结了毛竹Phyllostachys edulis入侵天然阔叶林影响土壤微生物特征的生物学机制。研究发现:入侵植物会提高入侵地土壤微生物生物量,增加土壤微生物多样性,为入侵创造有利土壤环境;入侵植物通过改变土壤微生物功能类群进而改变养分循环和其他环境条件,最终实现入侵。加强植物入侵对土壤微生物影响及其驱动的养分循环研究,阐明“植物—土壤”反馈机制,有助于预防和控制植物入侵。

上消化道癌前病变患者舌苔与土壤菌群相关性初步分析

目的:探讨扬中地区上消化道癌前病变患者舌苔与土壤菌群的相关性。方法:收集22例上消化道癌前病变患者的舌苔和自留地土壤,采用16S r DNA高通量测序检测菌群,生物信息学分析菌群多样性、菌群结构、共生关系等。结果:舌苔菌群多样性和丰富度均显著低于土壤,菌群组成显著不同。舌苔与土壤之间有17个分类单元(1门、2纲、3目、3科、4属和4种)显著相关。然而,舌苔与土壤菌群预测功能中脂质运输与代谢、翻译后修饰-蛋白翻转-蛋白伴侣、信号转导机制、防御机制等均为显著负相关,胞内运输-分泌-囊泡运输为显著正相关。结论:舌苔与土壤菌群存在相关性,土壤菌群可能是扬中地区上消化道癌地域性高发的关键因素。