Effect of Plant Growth-Promoting Rhizobacteria at Various Nitrogen Rates on Corn Growth

Plant growth-promoting rhizobacteria (PGPR) colonize plant roots and promote plant growth by producing and secreting various chemical regulators in the rhizosphere. With the recent interest in sustainable agriculture, an increasing number of researchers are investigating ways to improve the efficiency of PGPR use to reduce chemical fertilizer inputs needed for crop production. Accordingly, greenhouse studies were conducted to evaluate the impact of PGPR inoculants on biomass production and nitrogen (N) content of corn (Zea mays L.) under different N levels. Treatments included three PGPR inoculants (two mixtures of PGPR strains and one control without PGPR) and five N application levels (0%, 25%, 50%, 75%, and 100% of the recommended N rate of 135 kg N ha−1). Results showed that inoculation of PGPR significantly increased plant height, stem diameter, leaf area, and root morphology of corn compared to no PGPR application under the same N levels at the V6 growth stage, but few differences were observed at the V4 stage. PGPR with 50% of the full N rate produced corn biomass and N concentrations equivalent to or greater than that of the full N rate without inoculants at the VT stage. In conclusion, mixtures of PGPR can potentially reduce inorganic N fertilization without affecting corn plant growth parameters. Future research is needed under field conditions to determine if these PGPR inoculants can be integrated as a bio-fertilizer in crop production nutrient management strategies.

Plant Growth Promoting Rhizobacteria Having 1-Aminocyclopropane-1-Carboxylic Acid Deaminase to Induce Salt Tolerance in Sunflower (<i>Helianthus annus L.</i>)

Soil salinity badly affects agriculture productivity through accumulation of salts in upper layers of soils. The harmful effects of salts in arable lands have influenced modern as well as ancient civilizations. A pot study was carried out to test the performance of two PGPR isolates (KS 8, KS 28) on sunflower (SMH-0917) under different salinity levels (8, 10 and 12 dS·m-1). These salinity levels were developed by adding calculated amount of salts (NaCl, Na2SO4, CaCl2 and MgSO4) with ratio of 3:4:2:1. The bacterial strains KS 8 and KS 28 were applied separately in two treatments while third treatment was co-inoculation (KS mix). Completely randomized experimental design (CRD) was used and data were collected at flowering stage about pre-decided plant growth parameters (plant height, shoot dry weight and root dry weight). The bacterial isolate KS 8 showed an increase of 26, 102% and 83% in plant height, shoot dry weight and root dry weight at EC 8 dS·m-1, while this improvement was 67%, 163% and 296% at EC 10 dS·m-1, however an increase of 100%, 74% and 382% was recorded over control respectively at EC 12 dS·m-1. Similarly isolate KS 28 exhibited an increase of 14%, 69% and 54% in plant height;shoot dry weight and root dry weight at EC 8 dS·m-1, whereas this improvement was 56%, 163% and 188% at EC 10 dS·m-1, while an increase of 60%, 41% and 282% was registered respectively over control at EC 12 dS·m-1. The increase due to mixture treatments was 4%, 41% and 16% in plant height, shoot dry weight and root dry weight at EC 8 dS·m-1, while an increase of 33%, 57% and 100% at EC 10 dS·m-1, whereas an improvement of 53%, 33% and 164% respectively was noted at EC 12 dS·m-1 over un-inoculated. The isolate KS 8 performed better than KS 28 and mixture treatment. These two PGPR strains could be used to mitigate the adverse impact caused by salinity stress on sunflower.

Plant Growth Promoting Rhizobacteria as Biological Control Agent in Rice

The use of agrochemical products to combat diseases in crops has adverse effects on the environment and human health. Plant growth promoting rhizobacterium (PGPR) has been increasingly proposed as an eco-friendly alternative in agriculture. PGPRs have beneficial effects not only in promoting plant growth but also have shown their potential as biological control agent, being able to inhibit plant pathogens. Here, we investigated the use of PGPR Paraburkholderia sp. strain SOS3 to provide disease protection in rice (Oryza sativa L.). The antagonistic activity of SOS3 against five fungal pathogens of rice was assessed by dual culture on plates and on rice seedlings. The results showed that on plate assay, SOS3 inhibits the growth of Curvularia lunata, Rhizoctonia solani, Pyricularia oryzae, Helminthosporium oryzae, and Fusarium moniliforme by 17.2%, 1.1%, 8.3%, 32.5%, and 35.4%, respectively. When inoculated on rice seeds, SOS3 promotes seed germination and significantly reduces disease symptoms in plants infected with R. solani. These results suggest that SOS3 has a great potential to be used in rice agriculture to combat the “Sheath Blight” disease.

PGPR调控植物响应逆境胁迫的作用机制

盐碱、干旱等非生物胁迫是限制植物生长和产量的重要环境因子。植物根际促生菌(PGPR)是一类定殖于植物根系的有益微生物,利用其生物学功能制成的生物菌剂具有低成本、高效和环保等优点,不仅可促进植物生长与作物产量,还能提高植物对非生物胁迫的耐受性。本研究对PGPR定义和种类、生物学功能及其在植物响应盐碱、干旱、高低温及重金属等非生物胁迫中的作用加以综述,并对其未来研究方向进行展望,以期为今后PGPR介导植物抗逆性的研究与生物菌剂的开发和应用提供理论支撑。

Potential of Biostimulants Based on PGPR Rhizobacteria Native to Benin’s Soils on the Growth and Yield of Maize (<i>Zea mays </i>L.) under Greenhouse Conditions

The application of biostimulants in agriculture represents an environmentally friendly alternative while increasing agricultural production. The aims of the study were to develop solid biostimulants based on five rhizobacteria native to Benin’s soils and to evaluate their efficacy on the growth and biomass yield of maize under greenhouse conditions on ferrallitic and ferruginous soils. Clay and peat were used as a conservation binder for the preparation of the biostimulants. These binders were used alone or combined in the different formulations with maize flour and sucrose. 10 g of biostimulants were applied at sowing in pots containing five kilograms of sterilised soil. The experimental design was a completely randomised block of 24 treatments with three replicates. The results obtained showed significant improvements (P < 0.001) in height (49.49%), stem diameter (32.7%), leaf area (66.10%), above-ground biomass (97.12%) and below-ground biomass (53.98%) on ferrallitic soil with the application of the clay + Pseudomonas putida biostimulant compared to the control. On the other hand, the use of the peat biostimulant + Pseudomonas syringae was more beneficial for plant growth on ferruginous soil. The height, stem diameter, leaf area, above-ground biomass and below-ground biomass of the plants under the influence of this biostimulant were improved by 83.06%, 44.57%, 102.94%, 86.84% and 42.68%, respectively, compared to the control. Therefore, these results confirm that Rhizobacteria express their potential through biostimulants formulated on maize. The formulated biostimulants can later be used by producers to improve crop productivity for sustainable agriculture.

持续干旱下接种PGPR对核桃苗抗氧化系统的影响

为探讨植物根际促生细菌(PGPR)对持续干旱胁迫下核桃叶片抗氧化系统的影响,采用盆栽试验,以1年生核桃苗为试验材料,研究持续干旱胁迫下接种PGPR对核桃苗株高和茎粗、叶片ROS积累和膜脂过氧化产物以及抗氧化酶活性、非酶类抗氧化物质含量的影响。结果表明,与正常浇水相比,持续干旱胁迫使核桃苗的株高和茎粗显著降低19.47%和15.49%,叶片超氧阴离子(O_(2)^(-·))、过氧化氢(H_(2)O_(2))和丙二醛(MDA)含量显著升高,同时,叶片超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)与单脱氢抗坏血酸还原酶(MDHAR)活性以及还原型谷胱甘肽(GSH)含量均明显升高。在持续干旱逆境下接种PGPR则能显著促进株高和茎粗生长,有效减少叶片内ROS积累和MDA含量,显著提高叶片SOD、CAT、APX和MDHAR活性以及还原型抗坏血酸(AsA)、GSH含量,并不同程度提高叶片AsA/DHA(双脱氢抗坏血酸)和GSH/GSSG(氧化型谷胱甘肽)比值。以上分析认为,持续干旱逆境下核桃苗接种PGPR,可通过提高叶片抗氧化酶活性和非酶类抗氧化物质含量来有效清除活性氧,从而增强核桃苗的耐旱能力,促进其生长。

Complete genome sequence of Bacillus amyloliquefaciens YP6, a plant growth rhizobacterium efficiently degrading a wide range of organophosphorus pesticides

Bacillus amyloliquefaciens YP6,a plant growth promoting rhizobacteria,is capable of efficiently degrading a wide range of organophosphorus pesticides(OPs).Here,we report the complete genome sequence of this bacterium with a genome size of 4009619 bp,4210 protein-coding genes and an average GC content of 45.9%.Based on the genome sequence,several genes previously described as being involved in solubilizing-phosphorus,OPs-degradation,indole-3-acetic acid(IAA)and siderophores synthesis.Interestingly,compared with the genomes of B.amyloliquefaciens species,strain YP6 had larger genome size and the most protein-coding genes.Moreover,the four categories of“cell envelope biogenesis,outer membrane(M),”“translation,ribosomal structure and biogenesis(J),”“transcription(K),”and“signal transduction mechanisms(T)”were fewer.These differences may be related to extensive environmental adaptability of the genus B.amyloliquefaciens.These results expand the application potential of strain YP6 for environmental bioremediation,provide gene resources involved in OPs degradation for biotechnology and gene engineering,and contribute to provide insights into the relationship between microorganism and living environment.

PGPR联合不同添加量椰壳生物炭对镉污染土壤的修复效果

【目的】探究CSBC-PGPR-黑麦草联合修复体系对Cd污染黄壤土的修复效果。【方法】选取椰壳生物炭(coconut Shell Biochar,CSBC)耦合植物促生菌—伯克霍尔德氏菌(Burkholderia sp.)YXL1制备4种不同的生物炭材料,通过盆栽试验考察CSBC-PGPR-黑麦草联合修复体系修复前后黑麦草生物量、黑麦草中Cd富集量、土壤中Cd赋存形态及其理化性质、土壤酶活性等。【结果】相较于CK对照组,CSBCB(CSBC+YXL1)施用后黑麦草生物量最大增幅74.20%、有效态Cd最大增幅15.25%、黑麦草富集Cd最大增幅为434.90%;土壤理化性质有效提升,pH、全氮、有效磷最大提高了0.50个单位、0.48 g/kg和7.61 mg/kg;土壤脱氢酶、土壤脲酶、土壤酸性磷酸酶以及蔗糖酶活性较空白处理活性显著提高,最高分别提高了62.55%、70.05%、27.49%和73.57%。【结论】运用CSBC-PGPR-黑麦草联合修复体系强化黑麦草对Cd富集能力,有着良好的应用前景。

Increased ammonification,nitrogenase,soil respiration and microbial biomass N in the rhizosphere of rice plants inoculated with rhizobacteria

Azospirillum brasilense and Pseudomonas fluorescens are well-known plant growth promoting rhizobacteria.However,the effects of A.brasilense and P.fluorescens on the N cycles in the paddy field and rice plant growth are little known.This study investigated whether and how A.brasilense and P.fluorescens contribute to the N transformations and N supply capacities in the rhizosphere,and clarified the effects of A.brasilense and P.fluorescens on the N application rate in rice cultivation.Inoculations with A.brasilense and P.fluorescens coupled with N application rate trials were conducted in the paddy field in 2016 and 2017.The inoculations of rice seedlings included four treatments:sterile saline solution(M_(0)),A.brasilense(M_(b)),P.fluorescens(M_(p)),and co-inoculation with a mixture of A.brasilense and P.fluorescens(M_(bp)).The N application rate included four levels:0 kg N ha^(–1)(N_(0)),90 kg N ha^(–1)(N_(90)),180 kg N ha^(–1)(N_(180)),and 270 kg N ha^(–1)(N_(270)).The results indicated that the M_(bp) and M_(p) treatments significantly enhanced the ammonification activities in the rhizosphere compared with the M_(0) treatment,especially for higher N applications,while the Mbp and M_(b) treatments greatly enhanced the nitrogenase activities in the rhizosphere compared with the M_(0) treatments,especially for lower N applications.Azospirillum brasilense and P.fluorescens did not participate in the nitrification processes or the denitrification processes in the soil.The soil respiration rate and microbial biomass N were greatly affected by the interactions between the rhizobacteria inoculations and the N fertilizer applications.In the M_(bp) treatment,N supply capacities and rice grain yields showed no significant differences among the N_(90),N_(180),and N_(270) applications.The N application rate in the study region can be reduced to 90 kg N ha^(–1) for rice seedlings co-inoculated with a mixture of A.brasilense and P.fluorescens.

PGPR菌剂对攀西高原植烟土壤nifH基因群落的影响

为研究植物根际促生菌(PGPR)菌剂处理下攀西高原植烟土壤氮素循环的微生物调控机制,本研究以凉山州会理市不同PGPR菌剂(Lysinibacillus sp.、Streptomyces Phaeochromogenes和Aspergillus niger)处理下的植烟田为研究对象,采集烤烟成熟期根际土壤,通过化学分析和高通量测序技术对土壤理化性质、固氮酶活性及nifH基因群落组成及多样性进行分析。结果表明,与常规施肥相比,施用PGPR菌剂会显著降低植烟土壤的pH值,同时显著提高有效磷含量和固氮酶活性(P<0.05)。总体而言,施用PGPR菌剂提高了植烟土壤nifH基因群落的多样性。植烟土壤优势菌群为变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)和蓝菌门(Cyanobacteria)。慢生根瘤菌属(Bradyrhizobium)、地杆菌属(Geobacter)和固氮螺菌属(Azospirillum)等是植烟土壤优势属。冗余分析结果表明,植烟土壤pH值、碱解氮和速效钾含量与nifH基因群落结构相关性最强。综上,PGPR菌剂能改善植烟土壤养分状况,提高土壤固氮酶活性,影响植烟根际土壤nifH基因群落组成及多样性,其中以细菌PGPR菌剂Lysinibacillus sp.效果最佳。本研究结果为植烟土壤科学施肥、培肥地力提供了理论依据。

垂穗披碱草根际促生菌的分离鉴定及促生作用研究

优良的根际生长促生菌(Plant growth-promoting rhizobacteria, PGPR)是生产优质微生物菌肥的重要物质基础。本研究以广布于青藏高原的垂穗披碱草(Campeiostachys nutans Griseb.)为材料,采用平板划线法分离其PGPR,探究菌株的促生特性,通过16S测序确定菌株的分类地位,并进行盆栽试验验证PGPR的促生效果。结果表明,从垂穗披碱草根际土筛选出14株促生特性优良的PGPR,其中,有11株兼具产IAA,ACC脱氨酶以及铁载体的能力。经16S rDNA鉴定,以假单胞菌属为优势菌属,6株属于假单胞菌属(Pseudomonas),2株属于芽孢杆菌属(Bacillus),2株属于葡萄球菌属(Staphylococcus),其他四株分别属于类节杆菌属(Paenarthrobacter)、微杆菌属(Microbacterium)、不动杆菌属(Acinetobacter)和考克氏菌属(Kocuria)。盆栽试验表明,接种14株菌株对多年生黑麦草具有良好的促生效果,并能够提高其光合效率。研究结果丰富了植物根际促生菌菌种资源库,为实现农业“绿色增产”提供优质菌肥种质资源。

番茄疫霉根腐病菌拮抗细菌HP8-1的鉴定及生物防治潜力

【目的】探究HP8-1在番茄上的生物防治潜力,为番茄疫霉根腐病的生物防治提供优良生物防治资源。【方法】通过形态学观察、生理生化特性检测并结合16S rRNA序列分析鉴定HP8-1菌株,探讨其对植物病原菌的抑菌效果和生物学功能及在番茄根际的定殖能力,并通过盆栽试验测定其对番茄疫霉根腐病的防治效果和对番茄生长的影响。【结果】HP8-1为多粘类芽孢杆菌(Paenibacillus polymyxa),对多种植物病原菌具有抑菌效果,具有解磷、分解蛋白、分解纤维素、产嗜铁素和产吲哚乙酸等生物学功能;HP8-1在番茄根系和根际土壤具有稳定的定殖能力,尤其是在接种疫霉菌的条件下其定殖量趋于增加并显著高于未接种疫霉菌的条件;HP8-1处理对番茄疫霉根腐病具有明显的防治效果,防治效果达到57.41%;同时,HP8-1处理显著促进番茄植株生长、提高叶绿素含量和根系活力。【结论】HP8-1菌株稳定定殖在番茄根系和根际土壤,防治番茄疫霉根腐病,促进番茄生长,是对番茄疫霉根腐病具有生物防治潜力的资源。

根际促生细菌(PGPR)对冬枣根际土壤微生物数量及细菌多样性影响

从6年生冬枣根际土壤中筛选出1株根际促生细菌(PGPR),以发酵鸡粪(DC)为吸附载体制成PGPR生物肥(PF),利用传统的氯仿熏蒸法和现代的T-RFLP技术,从冬枣根际土壤中可培养微生物的数量、细菌群落多样性和微生物量碳的动态变化3个方面,分析PF、普通生物肥料(NF)和DC对冬枣根际土壤微生物特征的影响。结果表明:同NF处理相比,PF处理中的细菌数量和微生物总量显著增加,真菌数量显著减少,但放线菌数量差异不显著。PF处理根际土壤具有较高的丰富度指数、多样性指数和均匀度指数。基于T-RFLP的主成分分析结果表明:PF处理的细菌群落结构成为1个独立的群,NF,DC和CK处理构成1个相对独立的群。此外,同其他试验处理相比,PF可相对稳定地提供冬枣生长周期内的微生物生物量碳。PGPR生物肥料的施用可提高可培养微生物数量,提高根际土壤中微生物多样性,有效改善冬枣根际土壤的微生态环境。

植物根际优良促生菌(PGPR)筛选及其接种剂部分替代化肥对玉米生长影响研究

通过测定植物根际促生菌株固氮酶活性、溶磷量、分泌植物生长素、对病原菌的拮抗作用及菌株生长速度,筛选出了5株具有较好促生特性的优良菌株。利用筛选的优良菌株研制复合接种剂,并于2009年和2010年进行田试,测定其部分替代化肥对玉米生长的影响。结果表明:利用筛选的优良促生菌研制的复合微生物接种剂符合《微生物肥料》NY227-94标准。施用接种剂替代20%～30%的化肥,玉米株高、地上植物量、穗长、穗粗、单位面积穗数、穗粒数和经济产量等均有提高。研制的微生物接种剂(菌肥+80%化肥),2010年大田推广使用,玉米增产9.86%,减少化肥投入、增产收入及直接经济效益分别为620.1元.hm-2、2 291.4元.hm-2和2 851.5元.hm-2。

植物根际促生菌(PGPR)对缓解水稻受土壤锌胁迫的作用

为解决农田重金属污染的严重环境问题,提出利用植物根际促生菌(Plant growth-promoting rhizobacteria,PGPR)来缓解农作物受重金属胁迫的科学设想。研究从大宝山污染土壤中筛选出的Pb2+、Cd2+、Cu2+、Zn2+耐性菌株,经鉴定为芽孢杆菌属(Bacillussp.DBM),菌株DBM具有产吲哚乙酸(IAA)和ACC脱氨酶能力,但无产铁载体能力。盆栽试验结果表明,菌株DBM在水稻受重金属Zn(600mg.kg-1)胁迫时能有效保护并促进水稻的生长,使其地上部和地下部干重比不加菌处理对照分别提高97.8%和77.2%。另外,菌株DBM可以增加土壤中Zn的有效态含量,但不能增强水稻对土壤Zn的吸收能力。相反,在Zn600处理下,水稻地上部和地下部Zn浓度分别比不加菌处理对照减少15.1%和19.9%。但由于促生效果也极为显著,其地上部和地下部Zn总量仍分别比不加菌处理对照增加74.2%和48.6%。

植物根际促生细菌(PGPR)分离筛选与鉴定

【目的】从不同作物根际土壤中筛选对黄瓜和番茄有明显促生效应的植物根际促生细菌(PGPR)。【方法】从番茄、黄瓜、茄子、辣椒四种蔬菜作物的根际土壤中进行分离,测定菌株的促生能力,获得优势广适菌株,再根据菌体形态、培养特征及16S rDNA部分序列分析进行鉴定。【结果】共分离得到24株细菌菌株,经平皿初筛,分别筛选出对黄瓜幼苗、番茄幼苗生长有显著促生作用的细菌11和5株,再经营养钵促生实验筛选出2株对黄瓜、番茄幼苗均具有显著促生作用的PGPR菌,经16S rDNA序列分析,分别为芽孢杆菌属(Bacillus)和布克霍尔德氏菌属(Burkholderia)。【结论】所筛选细菌对黄瓜和番茄幼苗有显著促生作用,为进一步构建PGPR广适菌群提供了菌株资源。

促生菌种组合提高玉米根际土壤有益微生物基因丰度及促生效应研究

【目的】微生物肥料一般需要采用复合菌种提高有益菌在作物根际的定殖和促生效果。我们对本实验室前期分离鉴定的26个具有不同功能的玉米根际菌株进行复配,并研究复合菌株在土壤中的有益作用及其促生效果。【方法】按照功能共构建了4组合成菌群:C1,将铁载体分泌量最高的解磷菌、解钾菌、自生固氮菌、联合固氮菌各1株进行组合;C2,将吲哚乙酸(IAA)分泌量最高的解磷菌、解钾菌、自生固氮菌、联合固氮菌各1株进行组合;C3,每个菌属选择1株综合促生能力最强的菌株进行组合;C4,由C1与C2所有菌株组合。用以上4组菌群在灭菌土壤和未灭菌土壤上分别进行玉米接种菌剂和土壤浇灌菌剂盆栽试验,包括无菌剂对照在内共10个处理,灭菌土壤处理分别记为MCK、MC1、MC2、MC3、MC4,未灭菌土壤处理分别记为WCK、WC1、WC2、WC3和WC4。玉米接菌试验是将初生胚根长1~2 cm的玉米种子浸泡在菌群悬浮液中1 h,然后种植在灭菌土壤和未灭菌土壤中,9天后测定株高、鲜重、根长、根尖数和分叉数。土壤浇灌试验采用种子发芽方法,将种子播在灭菌和未灭菌土壤中,每5天浇灌1次菌悬液,待玉米生长15天后,收集玉米根际土壤用于宏基因组学测序,揭示菌群对玉米根际微生物的影响及其促生机制。【结果】4个复合菌剂相比,C4表现出最好的综合促生能力。玉米接种C4后,幼苗株高、地上鲜重、根鲜重、根长、根尖数和分叉数在灭菌组中分别比对照提高了28.97%、46.00%、59.99%、61.99%、62.27%和46.70%,在未灭菌组中分别提高了27.49%、25.86%、50.13%、40.11%、62.26%和82.55%。复合菌群C4提高了根际土壤中有益菌属Pseudomonas、Klebsiella、Duganella、Cellvibrio、Pantoea、Pseudoxanthomonas的丰度,在浇灌菌群C4的玉米根际土壤中,有益菌属Enterobacter和Klebsiella的注释丰度与对照组相比显著提高。菌群C4提高了根际土壤中磷和氮的转运、IAA的合成、铁载体的转运与调控系统和碳循环相关的功能基因的丰度,部分丰度上升的功能基因的微生物溯源分析结果显示,多数有益微生物的菌属丰度与功能基因丰度呈正相关,同时在ugqB、phnW的基因集中注释到了菌群C4的成员Klebsiella。【结论】菌群C4改变了玉米根际细菌群落组成,提高了有益菌属丰度,富集了促生相关功能基因,具备微生物复合菌肥开发的潜能。

植物促生菌暹罗芽孢杆菌37402-1的功能特性及对大蒜的促生效果

大蒜(Allium sativum L.)是我国的重要经济作物,主产地连作障碍严重,其种植生产的持续性受到制约。植物根际促生菌(PGPR)能够促进植物生长、防治病害且对环境友好。研制高效防控大蒜土传病害的微生物肥料对我国大蒜产业可持续发展和绿色发展有着重要的生态学和现实意义。以实验室前期从山东省金乡县连作大蒜根部分离的细菌为供试菌株,筛选获得对大蒜根腐病病原真菌尖刀镰孢菌(Fusarium oxysporum)ACCC37402和拟枝孢镰刀菌(Fusarium sporotrichioides)ACCC36464具有较好拮抗效果的菌株37402-1。菌株37402-1的PGPR功能特性研究结果显示:对大蒜根腐病病原真菌ACCC37402和ACCC36464的抑菌率分别为52.70%和37.98%;经16S rDNA基因序列同源性分析,确定为暹罗芽孢杆菌(Bacillus siamensis);具有水解蛋白能力、产铁载体能力、溶解有机磷和无机磷的能力。温室盆栽试验显示,接种暹罗芽孢杆菌37402-1菌悬液能够促进大蒜幼苗的生长。田间试验表明,接种暹罗芽孢杆菌37402-1菌剂使大蒜增产12.78%,并改变土壤酶活性(提高土壤蔗糖酶和土壤脲酶活性,降低土壤过氧化氢酶活性)。菌株暹罗芽孢杆菌37402-1兼具多种功能特性,对大蒜根腐病具有较好的拮抗效果,同时可以显著促进大蒜幼苗生长,并可在大田条件下促进大蒜的单产,有望开发成为高效的微生物肥料生产菌种。

使用PGPR菌剂及苜蓿培肥新垦地土壤研究

本研究以重庆北碚新垦坡耕地中性土壤为对象,采用裂区设计法研究种植紫花苜蓿并配施根际有盖微生物(PGPR)对紫花苜蓿生长及土壤微生物的影响.本研究涉及的PGPR菌包括根瘤菌、联合固氮菌、硅酸盐细菌和巨大芽孢杆菌.设置种植紫花苜蓿不接种(A)、种植紫花苜蓿接种根瘤菌(A+R)、种植紫花苜蓿接种PGPR(A+PG-PR)和空地(CK)等4个处理.结果显示:各处理对紫花苜蓿农艺品质、土壤微生物数量及土壤微生物生物量氮含量的影响程度大小顺序均为A+PGPR,A+R,A,CK;而对微生物生物量碳含量的影响大小顺序是A,A+PGPR,A+R,CK.与CK相比,接种PGPR处理显著提高了紫花苜蓿瘤质量、株高、根干质量、地上部干质量和全氮含量(p<0.05);接种PGPR较CK显著增加了土壤细菌、真菌、放线菌、根瘤菌、硅酸盐细菌和固氮菌数量(p<0.05);接种PGPR的土壤微生物生物量碳、氮含量较CK处理的分别显著提高了60.12%和63.28%(p<0.05);同时,该处理还显著提高了土壤的各项基本化学肥力指标.相关性分析表明,微生物生物量氮与植物全氮以及土壤养分各指标显著相关.研究表明,种植紫花苜蓿并配施PGPR能够显著增加新垦地土壤微生物数量,促进新垦地土壤培肥.

PGPR与AMF相互关系的研究进展

深入研究和揭示植物促生根圈细菌 (PGPR)与丛枝状菌根真菌 (AMF)在植物根圈内的相互关系 ,对于进一步利用和调控根圈微生物的相互作用 ,促进和保护植物生长 ,具有深远的意义 .大量研究结果表明 ,PGPR与AMF之间表现出互利作用 .AMF对PGPR在根部散布过程中可起转移和媒介的作用 ;PGPR也能为AMF在根部的感染创造有利条件 .而且它们可通过各自对植物生长的促进作用以间接提高对方在根圈的定殖或感染能力 .它们之间又存在着对营养及生态位的竞争 ,并可能产生一些次生代谢产物 ,从而给对方造成不利影响 ,但它们这种互利或竞争的相互作用存在着明显的种间特异性 .迄今为止 ,国内外对于它们相互关系的研究虽然面广 ,但在很多方面尚不系统 ,也不深入 .但可以相信 ,随着分子生物学技术的发展和先进检测手段的不断应用 。