解磷微生物修复土壤重金属污染研究进展

土壤重金属污染问题日益严重,具有普遍性、隐蔽性、表聚性、不可逆性等特点,已经成为环境污染治理中的热点、难点问题。解磷微生物能够依靠自身的代谢产物或通过与其他生物的协同作用,将土壤中的难溶性磷转化为可供植物吸收利用的磷,具有多重植物促生长功能和重金属解毒能力,可在重金属毒害水平下,促进植物生长、提高植物抗病能力、克服重金属对植物生长的不利影响,从而增强重金属修复植物的生存竞争力。从解磷微生物的研究现状入手,介绍了解磷微生物对土壤重金属污染的修复能力,综述了解磷微生物对土壤重金属污染修复的作用机制,分析了目前解磷微生物在重金属修复过程中存在的问题,并提出了今后研究的方向,为重金属污染土壤的修复提供了新思路。     

不动杆菌JL-1菌株的解磷机理

【背景】不动杆菌(Acinetobacter indicus) JL-1菌株可将土壤中难溶性磷转化为植物可吸收利用的可溶性磷,但其解磷机理尚不明确。【目的】探讨不动杆菌JL-1菌株的解磷机理。【方法】采用钼蓝比色法测定菌株在不同难溶性磷源中的解磷效果,确定最佳磷源;通过粒径测定法、超声破碎法、高效液相色谱法等多种方法,检测不动杆菌JL-1菌株在解磷过程中对磷酸钙的溶解作用、对磷的固化作用及产有机酸和磷酸酶酶活情况。【结果】不动杆菌JL-1菌株在磷酸钙液体培养基中解磷效果最佳,解磷量在48 h达到最高值118.04μg/mL。在解磷过程中,JL-1菌株对磷酸钙具有溶解作用,菌株自身固化了部分磷;可溶性磷的释放是发酵过程中产生的葡萄糖酸、丙酸、乙酸、乳酸等多种有机酸与磷酸酶共同作用的结果,有机酸中丙酸含量最高可达118.11 mg/mL;酸性磷酸酶酶活最高为22901.32μmol/(L·h),碱性磷酸酶酶活最高为23826.02μmol/(L·h)。【结论】不动杆菌JL-1菌株在解磷过程中对磷酸钙颗粒显示出一定的溶解作用,通过分泌有机酸和磷酸酶使可溶性磷释放,同时菌体固化了一部分磷,本研究为不动杆菌应用于农业生产提供了一定的实验数据参考。     

麦田土壤解无机磷细菌的分离、筛选及其解磷效果

通过选择性解磷细菌培养基从麦田土壤中分离、纯化解无机磷细菌,并用钼蓝比色法定量研究磷细菌的解磷效果。结果表明通过选择性平板分离,发现麦田土壤中有15个菌株有解无机磷的作用,根据菌株直径和其解磷圈的大小,确定解磷能力较强的菌株9个;经过进一步分离纯化,选出单一无杂菌的菌株7个。解磷菌株经摇瓶培养后,比色测定培养液中磷的含量,通过比较发现其中5个菌株的解磷效果要显著优于其它两个菌株（P=0.05）。     

一株高效解无机磷细菌BS06的鉴定及其解磷能力分析

【目的】对一株来源于广西甘蔗根际土壤的高效解无机磷细菌BS06的分类和解磷能力进行探讨,以期为解磷微生物在广西甘蔗生产上的开发和应用提供理论依据。【方法】通过形态观察、生理生化测定及16S rRNA基因序列同源性分析,进一步结合种特异的recA基因序列分析对解磷菌BS06进行分类鉴定;通过改变无机磷培养基中的碳源、氮源对菌株解磷能力的影响,分析菌株的解磷特性;通过盆栽试验了解菌株对甘蔗品种粤糖00236、桂糖28磷素吸收的影响。【结果】分类鉴定结果表明菌株BS06属于洋葱伯克霍尔德菌(Burkholderia cepacia);菌株在以乳糖为碳源条件下具有较强的解磷能力,其发酵液中水溶性磷含量为262.71 mg/L;在以硝酸钠为氮源条件下有较强解磷能力,其发酵液中水溶性磷含量达到305.85 mg/L;接种BS06菌株显著促进甘蔗组培苗的生长并提高甘蔗植株的含磷量。【结论】解磷细菌BS06具有较大的开发利用潜力。     

黄土高原天然和人工油松林根际土壤解磷细菌群落特征及其功能

为了揭示油松-根系微生物的互作关系及其对油松林分稳定性的影响,本研究选择陕西省黄龙县天然和人工油松林,采集油松根际与非根际土壤,测定非根际土壤化学特性,分离纯化根际土壤解磷(有机磷和无机磷)细菌,通过DNA基因测序鉴定解磷细菌,并测定解磷细菌的解磷能力。结果表明: 天然油松林非根际土壤中全碳(TC)、全氮(TN)含量以及C/N、N/P极显著高于人工油松林。2种油松根际土壤中共鉴定出20属65种解磷细菌,其中以芽孢杆菌属、链霉菌属和假单胞菌属为优势菌群;天然油松林根际解磷细菌多样性、丰富度和均匀度指数均高于人工油松林,而优势度指数低于人工油松林。链霉菌属与非根际土壤TC、TN和C/N、N/P呈正相关,而芽孢杆菌属和假单胞菌属与非根际土壤硝态氮、铵态氮、有效磷及全磷含量呈正相关。2种油松林根际土壤不同解磷细菌的解磷能力存在差异,其中天然和人工油松林根际共有的解磷细菌为假单胞菌Pseudomonas sp.34-5,其对磷酸钙的解磷能力最高,为11.40 μg·mL^-1;天然油松林根际独有的解磷细菌蕈状芽胞杆菌BF1-5对卵磷脂的解磷能力最高,为4.58 μg·mL^-1。该林区2种油松林根际解磷细菌菌群结构存在显著差异。与人工油松林相比,天然油松林根际土壤解磷细菌群落多样性更丰富且分布更均匀,解磷能力普遍高于人工林。     

解磷微生物研究及应用进展

磷是植物生长所必需的重要营养元素之一,以难溶性磷酸盐形式存在于土壤中,磷肥在施入土壤后,极易被土壤固定,难以被作物吸收利用,从而降低了磷肥的利用率。解磷菌通过酸解、酶解、降低土壤环境pH及其他方式溶解土壤中难溶性磷酸盐,供作物吸收利用。解磷菌种类繁多,其存在方式和数量受土壤环境、植物种类、人为扰动等因素影响。详细论述了磷在土壤中的存在方式,解磷菌种类、土壤中存在方式、解磷机理及目前的应用研究进展,为解磷菌的研究方向及使用方法提供参考。     

少花蒺藜草入侵对根际土壤磷细菌群落多样性的影响

[目的]入侵植物少花蒺藜草在磷元素受限的贫瘠沙质土壤中能够快速生长和种群扩张,形成单一优势群落。本文解析了少花蒺藜草在磷胁迫条件下对磷素的高效利用机制,以期为揭示其入侵机理提供理论依据。[方法]设置少花蒺藜草、冰草、狗尾草和空白对照4个处理,通过高通量测序技术,从土壤解磷微生物的角度分析各处理间土壤中解磷细菌的组成差异。[结果]少花蒺藜草入侵显著提高了土壤磷酸酶的活性和土壤解磷菌的群落多样性。PCA与UPGMA聚类结果表明,少花蒺藜草与狗尾草根际磷细菌物种组成相似性最大。LEfSe多级物种差异判别分析结果表明,少花蒺藜草根际显著富集且与其他处理有显著性差异的解磷菌类群为α-变形菌、链霉菌,其在少花蒺藜草对磷的吸收中可能起较为重要的作用。变形菌门、浮霉菌门和放线菌门与少花蒺藜草根际土壤中的全磷含量呈显著正相关,放线菌门与少花蒺藜草根际土速效磷含量有紧密联系。[结论]少花蒺藜草通过改变入侵地根际土壤的解磷菌群落结构间接影响根际土壤的磷素环境,从而利于自身生长。     

原生动物与解磷微生物协同解磷作用

磷是农业生产重要的限制因素之一,土壤生物包括原生动物和微生物在土壤磷素转化过程中起着重要的作用。通过纯培养和土壤培养试验发现,供试的原生动物能够提高磷矿粉的有效磷,土壤有效磷含量也显著增加。所溶解出来的磷很大一部分以无机磷酸盐的形式贮藏在细胞内,熏蒸时才释放出来,少部分磷转化为生物量磷。原生动物与解磷菌之间没有显著的相互促进作用。     

柑橘园土壤中解磷细菌多样性及其功能潜力分析

解磷细菌（phosphate solubilizing bacteria,PSB）是重要的农业微生物资源,能够促进柑橘根系对土壤磷的吸收,但是目前对柑橘园土壤中PSB资源的研究不多。本研究以有效磷含量低的华南柑橘园土壤为对象,利用平板培养分离技术调查了PSB的资源和多样性,并测定了PSB菌株的解磷活性。研究结果表明,柑橘园土壤中PSB资源丰富,分离到20个属的54个PSB菌株,其中链霉菌（Streptomyces）、北里孢菌（Kitasatospora）、副伯克氏菌（Paraburkholderia）、伯克氏菌（Burkholderia）、芽胞杆菌（Bacillus）和类芽胞杆菌（Paenibacillus）6个属的菌株分离频率较高;PSB菌株对磷酸钙的解磷活性高、对磷酸铁的解磷活性低,而卵磷脂的解磷活性介于二者中间;北里孢菌和类芽胞杆菌对三种磷源的解磷活性均高于均值,可能是潜在的高活性PSB;溶磷圈大小可以筛选帮助PSB,但是不能用于评价解磷活性大小。这些研究结果为从红壤柑橘园中分离PSB资源并应用PSB提高柑橘植株的磷营养提供了依据。     

菌丝室接种解磷细菌Bacillus megaterium C4对土壤有机磷矿化和植物吸收的影响

通过30μm尼龙网将根盒分成根室和菌丝室,菌丝室中的低磷土壤施加75 mg P/kg土壤的植酸钙,研究了菌丝室土壤中丛枝菌根(AM)真菌Glomus intraradices和解磷细菌Bacillus megaterium C4对有机磷的矿化和吸收.结果表明,在试验条件下,植酸钙的溶解性很低,对土壤溶液有机磷的贡献不大.接种解磷细菌C4提高了土壤中磷酸酶的活性,减少了土壤中有机磷的含量.但是,由于存在解磷细菌与AM真菌对磷的竞争,解磷细菌矿化出的磷大部分被自身利用,AM真菌的生长受到抑制,解磷细菌对植物磷营养的改善没有表现出显著的贡献.     

解磷黑曲霉L-1菌株原生质体诱变育种

以从龙泉山地区酸性红壤中分离的黑曲霉L-1(Aspergillus niger sp.L-1)为出发菌株,通过研究菌株L-1原生质体的形成和再生条件,发现培养30 h的菌丝体在以0.15 mol/L氯化钾为渗透压稳定剂的基本培养基上经过再次培养20 h后,所得菌丝体用0.3%纤维素酶和0.4%蜗牛酶在30 ℃条件下处理...     

Thermo-tolerant phosphate-solubilizing microbes for multi-functional biofertilizer preparation

In order to prepare the multi-functional biofertilizer, thermo-tolerant phosphate-solubilizing microbes including bacteria, actinomycetes, and fungi were isolated from different compost plants and biofertilizers. Except Streptomycesthermophilus J57 which lacked pectinase, all isolates possessed amylase, CMCase, chitinase, pectinase, protease, lipase, and nitrogenase activities. All isolates could solubilize calcium phosphate and Israel rock phosphate; various isolates could solubilize aluminum phosphate, iron phosphate, and hydroxyapatite. During composting, biofertilizers inoculated with the tested microbes had a significantly higher temperature, ash content, pH, total nitrogen, soluble phosphorus content, and germination rate than non-inoculated biofertilizer; total organic carbon and carbon-to-nitrogen ratio showed the opposite pattern. Adding these microbes can shorten the period of maturity, improve the quality, increase the soluble phosphorus content, and enhance the populations of phosphate-solubilizing and proteolytic microbes in biofertilizers. Therefore, inoculating thermo-tolerant phosphate-solubilizing microbes into agricultural and animal wastes represents a practical strategy for preparing multi-functional biofertilizer.     

Minerals solubilizing and mobilizing microbiomes: A sustainable approach for managing minerals’ deficiency in agricultural soil

Agriculture faces challenges to fulfil the rising food demand due to shortage of arable land and various environmental stressors. Traditional farming technologies help in fulfilling food demand but they are harmful to humans and environmental sustainability. The food production along with agro-environmental sustainability could be achieved by encouraging farmers to use agro-environmental sustainable products such as biofertilizers and biopesticides consisting of live microbes or plant extract instead of chemical-based inputs. The eco-friendly formulations play a significant role in plant growth promotion, crop yield and repairing degraded soil texture and fertility sustainably. Mineral solubilizing microbes that provide vital nutrients like phosphorus, potassium, zinc and selenium are essential for plant growth and development and could be developed as biofertilizers. These microbes could be plant associated (rhizospheric, endophytic and phyllospheric) or inhabit the bulk soil and diverse extreme habitats. Mineral solubilizing microbes from soil, extreme environments, surface and internal parts of the plant belong to diverse phyla such as Ascomycota, Actinobacteria, Basidiomycota, Bacteroidetes, Chlorobi, Cyanobacteria, Chlorophyta, Euryarchaeota, Firmicutes, Gemmatimonadetes, Mucoromycota, Proteobacteria and Tenericutes. Mineral solubilizing microbes (MSMs) directly or indirectly stimulate plant growth and development either by releasing plant growth regulators; solubilizing phosphorus, potassium, zinc, selenium and silicon; biological nitrogen fixation and production of siderophores, ammonia, hydrogen cyanide, hydrolytic enzymes and bioactive compound/secondary metabolites. Biofertilizer developed using mineral solubilizing microbes is an eco-friendly solution to the sustainable food production system in many countries worldwide. The present review deals with the biodiversity of mineral solubilizing microbes, and potential roles in crop improvement and soil well-being for agricultural sustainability.     

氮磷添加和栽植密度对大叶相思林土壤微生物群落功能多样性的影响

土壤微生物群落是土壤质量潜在的生态指标,在维持生态系统功能和服务中起着关键的作用。采用Biolog-ECO微平板法,探讨氮磷添加与不同栽植密度交互对大叶相思林(Acacia auriculiformis)土壤微生物功能多样性的影响,以便为建立合理的林分密度和氮磷施肥模式,提高土壤质量提供理论参考。以大叶相思林为研究对象,选择氯化铵(NH4Cl)作为氮肥模拟大气氮沉降,用二水合磷酸二氢钠(NaH2PO4·2H2O)进行磷添加。氮磷处理设置4个水平,即CK、施N、施P和施N+P。种植密度设置4个水平,即1667、2500、4444、10000株/hm²(分别以低密度、中密度、较高密度、高密度表示)。研究结果表明,施P显著提高了4个密度大叶相思林土壤微生物的AWCD值、碳源利用丰富度指数、McIntosh指数、Shannon指数和Simpson指数,而施N和N+P则相反。随着林分密度的减小,各处理的土壤微生物AWCD值趋于减少。通常低密度林分的土壤微生物的丰富度指数、Shannon-Wiener指数、McIntosh指数和Simpson指数较小。     

土壤磷含量与有效性对N2O排放量的影响元分析

土壤氧化亚氮(N₂O)主要产生于土壤微生物参与的氮循环过程,其排放量受磷含量及有效性影响。添加磷肥有助于缓解陆地生态系统磷限制,提升土壤有效磷含量,进一步影响土壤微生物对氮的利用,同时控制N₂O排放。然而不同独立实验中N₂O对外源磷添加的响应差异较大。研究从发表的中、英文文献中收集了54份关于施用磷肥与N₂O排放量的观测结果,采用元分析方法确定添加外源磷后N₂O排放量的响应差异及潜在影响因素。结果表明：(1)外源磷添加对土壤N₂O排放量影响不显著;但在磷肥施用量> 50 kg P/hm²的室外实验中土壤N₂O排放量显著降低了32.5%;施用NaH₂PO₄的室内实验中N₂O排放量显著降低了18.4%。(2)土壤N₂O对外源磷添加响应的高变异性是磷肥施用量和土壤含水量、土壤pH、土地利用类型、磷肥种类、纬度和实验时间多种影响...     

割草和放牧对大针茅根际与非根际土壤养分和微生物数量的影响

选取内蒙古典型草原大针茅为主要研究对象,研究割草和放牧干扰对其根际与非根际土壤有机碳、全氮、有效氮、全磷、有效磷含量以及微生物数量的影响.结果表明：在割草和放牧干扰下,根际土壤有机碳、全氮、有效氮含量均有不同程度的减少,根际截存效应减弱;土壤全磷由于固定性强不易向植物根部聚集,土壤全磷的根际效应不明显;土壤有效磷异质性较大,在放牧和割草干扰下有不同程度的变化,但根际和非根际间差异不显著;放牧干扰显著减少了土壤微生物的数量;土壤养分的变化与土壤微生物数量的变化关系密切,细菌和真菌的数量变化可能对土壤养分的影响更大;相对于割草,放牧干扰更易造成根际土壤养分的流失及微生物数量的减少.     

Soil microbial biomass and the fate of phosphorus during long-term ecosystem development

Background

Soil phosphorus availability declines during long-term ecosystem development on stable land surfaces due to a gradual loss of phosphorus in runoff and transformation of primary mineral phosphate into secondary minerals and organic compounds. These changes have been linked to a reduction in plant biomass as ecosystems age, but the implications for belowground organisms remain unknown.

Methods

We constructed a phosphorus budget for the well-studied 120,000 year temperate rainforest chronosequence at Franz Josef, New Zealand. The budget included the amounts of phosphorus in plant biomass, soil microbial biomass, and other soil pools.

Results

Soil microbes contained 68–78 % of the total biomass phosphorus (i.e. plant plus microbial) for the majority of the 120,000 year chronosequence. In contrast, plant phosphorus was a relatively small pool that occurred predominantly in wood. This points to the central role of the microbial biomass in determining phosphorus availability as ecosystems mature, yet also indicates the likelihood of strong competition between plants and saprotrophic microbes for soil phosphorus.

Conclusions

This novel perspective on terrestrial biogeochemistry challenges our understanding of phosphorus cycling by identifying soil microbes as the major biological phosphorus pool during long-term ecosystem development.     

漓江河岸带不同水文环境土壤微生物与土壤养分的耦合关系

基于漓江河岸带典型地段内砾石滩、草地、灌草地和疏林地等4类水文环境梯度上的土壤样品分析,探讨了漓江河岸带土壤养分、微生物数量及微生物量等的变化特征及耦合关系。结果表明:土壤养分含量、土壤微生物数量及微生物量等在不同水文环境下均有显著差异。随着水淹时间的减少,土壤含水量、pH值、有效氮、有效磷和有效钾均呈先增后减的趋势,最大值多出现在灌草地,最小值多出现在砾石滩,而土壤微生物总量、细菌、放线菌数量和微生物量也为先增后减趋势,其数量或含量在灌草地最多,砾石滩最少。简单相关分析表明漓江河岸带各微生物指标与土壤有效氮、有效磷及速效钾相关性较强,与土壤全氮、全磷和全钾的相关性较弱。冗余分析表明土壤有效氮、有效磷和含水量是影响微生物总数、细菌数量、微生物量碳、微生物量氮和微生物量磷的重要因素,而有机质和全氮是影响放线菌数量的重要因素。研究结果说明适当的水文干扰有利于河岸带土壤养分的积累,对土壤微生物数量及其生物量也有显著促进作用;土壤有机质和有效养分含量(有效氮、有效磷等)与微生物数量及微生物量关系密切,其含量很大程度影响着微生物数量及其活性。在漓江河岸带生态保护和评估等研究过程中应充分考虑不同水文环境下的土壤微生物和养分的变化特征及耦合关系。     

Phosphorus availability increases pathobiome abundance and invasion of rhizosphere microbial networks by Ralstonia

Soil disease-suppressiveness depends on complex interactions among pathogens, native microbiota, and physicochemical properties, while these interactions remain understudied. Comparing field and microcosm experiments, we investigated the significance of these interactions in disease emergence or suppression using structural equation modelling (SEM) and receiver operating characteristic curve (ROC) analyses. We observed significant differences in the relative abundance of pathogenic and beneficial microbes, alpha and beta diversity indices between disease-conducive and -suppressive rhizosphere soils. The pathogenic (Ralstonia) and beneficial (Bacillus) taxa dominated disease-conducive and -suppressive rhizosphere soils, respectively. Moreover, the co-occurrences of Ralstonia with native microorganisms were positive and negative in the disease-conducive and -suppressive soils, respectively. These results suggest the supportive (Rudaea) and suppressive (Enterobacter, Bacillus) role of indigenous microbes in the invasion of soil and plant systems by Ralstonia. The SEM and ROC analysis predicted that Ralstonia invaded rhizospheric microbial networks and caused peanut wilt under high than low soil phosphorus conditions. Our results suggest the importance of soil phosphorus availability in altering the microbial interactions, thus leading to soil invasion by Ralstonia. Thus, we conclude by saying that feeding soil with high amounts of available phosphorus could deplete plant-beneficial microbes and increase the pathobiome abundance that may compromise plant health.