硅酸盐细菌肥有效活菌的确认与判定

把硅酸盐细菌培制成菌肥 ,施于土壤中 ,具有多方面的综合功效 ,因此它是菌肥中有发展前途的一种。近几年来 ,多种微生物肥料在我国已由研究转入应用阶段 ,因而对其质量的监控就显得尤为重要 ,而有效活菌数是菌肥质量好坏的关键指标之一 ,虽然 NY2 2 7- 94微生物肥料标准对一些菌肥有效活菌数的测定用平板计数法作了规定 ,但其对平板上菌落的辨认、菌的染色确认及有效活菌数的判定方法未做具体说明 ,笔者根据近年检测实践 ,对硅酸盐细菌肥有效活菌数的测定在这方面作了较多实践。1　菌落的辨认按 NY2 2 7- 94微生物肥料标准方法操作 ,将菌…     

ATP发光技术测定辐照前脱水蔬菜和调味品的含菌量

用ATP发光技术测定脱水蔬菜和调味品的初始含菌量,发现脱水蔬菜和调味品中细菌ATP的生物发光强度与其初始含菌量之间显著相关,从样品的制备到获得ATP发光强度结果的检测过程仅需1～2h。该技术可用于辐照灭菌前的微生物检测。     

氯氰菊酯污染土壤的微生物修复及对土著微生物的影响

在实验室条件下,在含有氯氰菊酯的土壤中添加氯氰菊酯和3-苯氧基苯甲酸(3-PBA)降解菌CDT3(Rhodococcussp.)和PBM11(Pesudomonassp.),同时设不加菌的对照。分别于0、3、7、15、30 d取样,测定土壤中氯氰菊酯和3-PBA的残留,同时用平板计数和变性梯度凝胶电泳(DGGE)方法分析土壤微生物群落的变化。结果显示:CDT3和PBM11在土壤中协同作用能够更好地降解氯氰菊酯及其中间产物3-PBA。氯氰菊酯对土著微生物有较强的抑制作用。投加降解菌可以消除农药对土壤微生物的抑制,有助于土著微生物种群的恢复,但短期内无法改变农药对土壤微生物结构的破坏。     

秸秆育苗容器在土壤中降解对微生物区系的影响

为了阐明秸秆育苗容器降解过程中对土壤及容器残体酶活性及微生物的影响,选择淀粉胶秸秆育苗容器(MSGC)和豆胶秸秆育苗容器(MBGC)两类容器的片状试材进行土培试验,设计不含容器试材土壤为对照组(CK),试验持续45 d,采用常规分析和BiologEco微平板计数技术手段测定了容器残体及土壤中的酶活变化、微生物群落多样性、菌群数量及功能多样性。结果表明:土培过程中,容器和土壤中酶活总体呈上升趋势,MSGC淀粉酶活与MBGC无显著差异,纤维素酶活初期显著高于MBGC,中后期则无显著差异。蛋白酶活MBGC全过程显著高于MSGC;秸秆容器可显著提高土壤磷酸酶和脲酶酶活,与MBGC相比,MSGC土壤中磷酸酶和脲酶酶活更高。Biolog~(Eco)分析显示,秸秆容器能够显著提高土壤中微生物碳源利用活性,土壤平均颜色变化率(AWCD)值先增大后减少,MBGC与MSGC差异在于后者土壤AWCD值下降速率显著快于前者。两种容器残体微生物功能多样性初期差异显著,后期差异减少。与MSGC比,MBGC土壤微生物对氨基酸、聚合物及胺类利用具有更强活性,这种差异主要与容器胶粘剂不同有关。本研究结果将为秸秆育苗容器田间应用与生态效应评价提供理论依据。     

添加葡萄糖和胞外多糖条件下土壤细菌多样性与青枯病病原菌入侵关系研究

微生物多样性、病原菌入侵及微生物群落物质利用的关系尚未系统阐明。本研究通过土壤悬液梯度稀释并外源添加方法构建不同多样性的微生物群落,借以研究土壤微生物多样性与青枯病病原菌(青枯菌)入侵的关系,并通过添加低分子量葡萄糖和高分子量胞外多糖探索物质添加对土壤微生物多样性与病原菌入侵关系的影响。结果表明土壤悬液梯度稀释并外源添加方法能有效构建不同多样性的微生物群落。随着森林和菜地土壤微生物多样性的上升,青枯菌入侵成功率均逐渐降低。此外,添加葡萄糖至不同微生物多样性土壤中均能显著促进青枯菌的生长,而胞外多糖仅在土壤微生物多样性较高时(即竞争较为激烈时)可体现对青枯菌生长的促进作用。综上,土壤微生物多样性与病原菌入侵成功率呈负相关关系,这一关系受土壤微生物群落来源影响较小,物质添加能降低微生物多样性对病原菌入侵的抑制能力,但是该效应与碳源的性质有关。     

鸡蛋超弱发光与其新鲜程度的相关分析

使用超弱发光图像探测系统研究了鸡蛋在贮藏期中的发光情况，发现不同鸡蛋的发光强度在第3天达到最大，随后又表现出振荡衰减，这说明第3天的鸡蛋活性最强；对鸡蛋延迟发光进行了研究，发现普遍服从双曲衰减规律，这一点与生物光子的相干理论相一致。不同鸡蛋的超弱发光强度是不同的，这与鸡蛋生命活动的强弱有关，生命力越旺盛的鸡蛋发光也就越强。超弱发光作为鸡蛋生理生化反应的综合指标，用于测定鸡蛋鲜度，方法简单、无损伤、灵敏度高；它不仅可以用来检测鸡蛋的鲜度，还可以检测其它方法难以反映或不能反映的鸡蛋随各种外界条件（如光照、温度等）的变化规律。     

重金属污染土壤毒性的发光菌法与斜生栅藻法诊断

应用斜生栅藻(Scenedesmus obliquus)和明亮发光杆菌T3(Phyotobacterium Phosphoreum)对重金属污染土壤的毒性进行诊断,结果表明,斜生栅藻的增长率和发光菌的相对发光度与土壤中的重金属含量明显相关,并且随重金属投加量的增加,其增长率和发光度逐渐降低,对3种测试参数进行比较,发现采用细胞数增长率作为土壤毒性的检测指标比采用光密度增长率和相对发光度更为敏感。复合污染情况下,由于金属间的协同作用,使土壤的毒性比单一重金属污染时有明显的增强,从而为污染土壤的优先修复提供了理论依据。     

延边烟区不同土壤的根际土壤微生物生态效应研究

为揭示烤烟根际微生物数量及酶活性的变化规律,阐明烤烟-土壤-微生物之间的协同作用机理,在延边烟区采集不同土壤类型的烤烟根际土壤,研究了烤烟根际土壤微生物生态效应.结果表明:不同土壤条件下烤烟各时期根际微生物区系和微生物生理菌群数量存在着较大的差异,其中暗棕壤黏土和暗棕壤黑砂土比白浆土更适合细菌和解钾菌的生长,白浆土真菌数的变化幅度较大可能是引起烟叶质量变差的原因之一,暗棕壤黏土和暗棕壤黑砂土在烤烟生育期内放线菌数量的变化较大,明显大于白浆土;自生固氮菌在移栽后 60 天前数量均较低,60 天后急剧升高,100 天时暗棕壤黏土和暗棕壤黑砂土自生固氮菌数量显著高于白浆土;氨化菌生长的最适宜期出现的早晚顺序为:暗棕壤黏土＞暗棕壤黑砂土＞白浆土;生育期内根际土壤解磷菌数变化较大,暗棕壤黏土烟株在旺盛生长时期的解磷菌数显著高于其他 2 种类型土壤.过氧化氢酶活性的变化规律很大程度上受土壤类型的影响,而转化酶和多酚氧化酶变化受土壤类型影响较小,但两者的大小受土壤类型的影响.     

定位培肥对黑土农田生态系统中土壤微生物活性的影响

通过定位培肥试验对不同培肥方式下黑土生态系统中的土壤微生物活性进行了研究。研究结果表明,不同培肥处理均提高了土壤细菌、富营养菌和寡营养菌的数量,且农肥处理优于化肥处理,单施化肥处理土壤的富营养菌数量苗期最高,而农肥处理和农肥化肥等量处理为先升高后降低,至鼓粒期土壤中的富营养菌数量降至最低。施肥处理土壤微生物量的含量高于对照,农肥处理和农肥化肥等量处理的土壤中微生物量碳、氮含量高于单施化肥处理。不同培肥处理均提高了土壤脲酶的活性,施肥处理土壤脲酶的活性的变化范围为79.56～139.90mg/100g土,农肥低量和农肥高量处理土壤过氧化氢酶之间差异不显著,但显著高于对照,农肥处理土壤过氧化氢酶的含量始终是最高的,平均为0.41ml KMnO4/g干土,农肥化肥等量处理、化肥低量处理和化肥高量处理之间差异不显著,土壤过氧化氢酶含量平均为0.37ml KMnO4/g干土。因此,施用农肥是增加土壤微生物活性的有效途径,有利于提高退化土壤的质量。     

绿豆幼苗的超弱发光规律及盐胁迫下的变化

为了研究绿豆幼苗的超弱发光规律及盐胁迫对其的影响和改变,本研究首次采用以EMCCD（电子倍增式CCD）为主的、自行搭建的超弱光图像探测系统,以豫绿2号绿豆为实验材料,检测了绿豆幼苗的自发超弱发光以及在盐胁迫下的改变情况。结果发现：绿豆幼苗自发发光的强度远小于延迟发光的强度,不同的盐胁迫时间对延迟发光强度和自发发光强度的影响各不相同,故可以用延迟发光强度的变化来表征盐胁迫对植物的伤害程度。实验数据的统计结果表明：盐胁迫下绿豆幼苗的发光强度-时间曲线遵循指数衰减规律,说明生物光子具有一定的相干性。本文结果将为农田实时监测植物盐胁迫生理状况提供一种新的光子学手段。     

二(2-乙基己基)邻苯二甲酸酯降解菌的分离和鉴定及其在污染土壤生物修复中的作用

Di-（2-ethylhexyl） phthalate（DEHP） is a high-molecular-weight phthalate ester（PAE） that has been widely used in the manufacture of polyvinylchloride and contributes to environmental pollution.The objectives of the present study were to isolate a DEHP degrader that can utilize DEHP as a carbon source and to investigate its capacity to biodegrade DEHP in both liquid culture and soil.A bacterial strain WJ4 was isolated from an intensively managed vegetable soil,which was contaminated with PAEs.The strain WJ4 was affiliated to the genus Rhodococcus and was able to remove DEHP from soil effectively.A period of only 7 d was required to degrade about 96.4%of DEHP(200 mg L^-1) in the liquid culture,and more than 55%of DEHP(1.0 g kg^-1) in the artificially contaminated soil was removed within 21 d.Furthermore,Rhodococcus sp.strain WJ4 had a strong ability to degrade DEHP without additional nutrients in liquid minimal medium culture and DEHP-contaminated soil and to degrade the homologue of DEHP in both liquid culture and soil.Strain WJ4 represents a novel tool for removing PAEs from contaminated soils and it may have great potential for application in the remediation of environmental pollution by PAEs.     

Phosphate solubilizing microorganisms isolated from rhizosphere of maize cultivated in an oxisol of the Brazilian Cerrado Biome

Many soil microorganisms are able to transform insoluble forms of phosphorus to an accessible soluble form, contributing to plant nutrition as plant growth-promoting microorganisms (PGPM). The objective of this work was to isolate, screen and evaluate the phosphate solubilization activity of microorganisms in maize rhizosphere soil to manage soil microbial communities and to select potential microbial inoculants. Forty-five of the best isolates from 371 colonies were isolated from rhizosphere soil of maize grown in an oxisol of the Cerrado Biome with P deficiency. These microorganisms were selected based on the solubilization efficiency of inorganic and organic phosphate sources in a modified Pikovskaya's liquid medium culture containing sodium phytate (phytic acid), soybean lecithin, aluminum phosphate (AlPO₄), and tricalcium phosphate (Ca₃(PO₄)₂). The isolates were identified based on nucleotide sequence data from the 16S ribosomal DNA (rDNA) for bacteria and actinobacteria and internal transcribed spacer (ITS) rDNA for fungi. Bacteria produced the greatest solubilization in medium containing tricalcium phosphate. Strains B17 and B5, identified as Bacillus sp. and Burkholderia sp., respectively, were the most effective, mobilizing 67% and 58.5% of the total P (Ca₃(PO₄)₂) after 10 days, and were isolated from the rhizosphere of the P efficient L3 maize genotype, under P stress. The fungal population was the most effective in solubilizing P sources of aluminum, phytate, and lecithin. A greater diversity of P-solubilizing microorganisms was observed in the rhizosphere of the P efficient maize genotypes suggesting that the P efficiency in these cultivars may be related to the potential to enhance microbial interactions of P-solubilizing microorganisms.     

百菌清降解菌株H4的分离与表征及其修复污染土壤的潜能研究

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 16 S r DNA 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 p H values, and the optimum conditions for H4 degradation were p H 7.0 and 30℃. 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 plate TM 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.     

荧光假单胞菌Pf.X16L2与丛枝状菌根真菌Glomus mosseae在小麦根圈内的相互关系

运用发光酶基因标记及其发光强度检测,SDH酶活染色等技术,在根盒－土壤微宇宙及塑料盒栽系统中,研究了发光酶基因（luxAB)标记的荧光假单胞菌菌株Pf.X16L2与丛枝状菌根真菌摩西球孢囊霉Glomus mosseae两者在小麦根圈的相互关系。Gl.mosseae对Pf.X16L2的种群密度和生理活性都有着抑制作用。因而能降低小麦根圈对Pf.X16L2的富集作用,而Pf.X16L2在一定程度上能提高Gl.mosseae的菌根感染率,但会降低菌丝中琥珀酸氢酶（SDH）活性,两者可共同促进小麦中后期的生长。     

砂姜黑土中兼具促生功能的纤维素降解菌的筛选及其应用

为实现砂姜黑土地区秸秆资源化利用以及作物增产，本研究从该区小麦-玉米轮作土壤中筛选具有促生功能的纤维素降解菌株。通过羧甲基纤维素酶活(CMC)与吲哚乙酸(IAA)分泌量测定，筛选出1株具有高效降解纤维素的促生菌株。经形态学和分子生物学鉴定，该菌株为普沙根瘤菌(Rhizobium pusense)，命名为X2。小麦秸秆降解和玉米盆栽初步试验结果显示，X2菌株经液态发酵15d后小麦秸秆降解率为16.1%，较对照显著提升65.4%；接种该菌株后盆栽土壤中碱解氮含量较对照显著提高了72.7%，植株根系的平均直径、表面积以及地上部干物质量显著增加了22.0%、28.6%和33.3%。为进一步提高该菌株的活性，采用单因素试验对菌株的培养条件进行优化，结果表明，X2菌株在装液量为25 mL/250 mL、氮源为酵母粉、pH为6.0时生长和产IAA能力最优，产酶的最适pH为5.0。综上，所筛菌株X2具有秸秆降解和玉米促生能力，可在砂姜黑土地区为秸秆资源化利用提供新的微生物资源。     

Light-stimulated 14CO2 uptake and acetylene reduction by bacteriochlorophyll containing stem nodule isolate BTAi 1

Summary Bradyrhizobial strain BTAi 1 nodulates both stems and roots of Aeschynomene spp. Previous work has shown that it contains bacteriochlorophyll a and forms photosynthetic reaction centers, and has provided indirect evidence of photosynthesis by bacteroids within stem nodules. Here we report physiological and biochemical characteristics of BTAi 1 ex planta, which also suggest the presence of photosynthetic activity. Light-stimulated uptake of ¹⁴CO₂ by BTAi 1 was detected at all stages of growth. Inhibitors of photosynthesis, 1,10-orthophenanthroline and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), and the uncoupler NH₄Cl, immediately suppressed light-driven ¹⁴CO₂ uptake and increased O₂ uptake. BTAi 1 is strictly aerobic and was unable to grow without organic C even in the light; also, it was unable to grow chemoautotrophically in an atmosphere enriched with H₂ and CO₂. In micro-aerobic conditions, strain BTAi 1 expressed acetylene reducing activity ex planta in an N-free medium. The highest rates of light-stimulated ¹⁴CO₂ uptake and acetylene-reducing activity occurred during the exponential and early stationary phases of growth. Acetylene-reducing rates at a low glucose concentration were increased following a light-dark cycle in comparison with continuous dark conditions.     

两株解磷细菌的解磷活性及作用机制研究

解磷细菌在增加土壤可溶性磷含量、提高磷肥利用效率方面具有重要作用。为选筛高效解磷菌、探讨其解磷机制,本文利用平板溶磷圈法筛选解磷细菌,采用钼锑抗比色法研究其解磷活性,苯磷酸二钠法研究其磷酸酶活性,利用薄层层析分析其产生的有机酸,根据生理生化特征和16S r RNA基因序列系统发育分析,确定其分类学地位。结果表明,菌株JXJ-11和JXJ-15对植酸钙的降解活性很强,3 d后培养液中可溶性磷浓度分别增加219 mg·L~(-1)和216 mg·L~(-1);对磷酸钙降解活性较弱,最高可溶性磷浓度仅为植酸钙的21.79%~30.37%;解磷细菌可分泌酸性、中性和碱性磷酸酶,降解不溶性磷,可能产生丙酸和琥珀酸等有机酸,降低培养液p H,增加可溶性磷浓度。两株细菌均为革兰氏阴性杆菌,无芽孢,产生硫化氢,其中菌株JXJ-11的16S rRNA基因序列与Sphingomonas melonis DAPP-PG 224T和S.aquatilis JSS7T相似性最高(99.79%),菌株JXJ-15的16S rRNA基因序列与Klebsiella pneumoniae subsp.pneumoniae DSM 30104T相似性最高(99.73%),根据以上信息,确定菌株JXJ-11和JXJ-15分别是鞘氨醇单胞菌属和克雷白氏杆菌属的成员。菌株JXJ-11和JXJ-15的解磷机制包括分泌有机酸和磷酸酶,其中JXJ-11在微生物磷肥研制方面具有潜在应用价值。     

Variable effects of emergence-promoting rhizobacteria on conifer seedling growth under nursery conditions

Summary Inoculation of white spruce (Picea glauca Voss.) seed with Bacillus polymyxa strain L5 under nursery conditions significantly increased the number of seedlings that emerged after sowing. No significant effects on seedling emergence were detected when white spruce seed was inoculated with Bacillus polymyxa strain L6, or when Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] seed was inoculated with either strain L5 or L6. However, white spruce seedlings originating from L5-inoculated seed had significantly lower root dry weights when measured 13 weeks after sowing, and reduced shoot dry weights 26 weeks after sowing compared with uninoculated controls. Inoculation of white spruce seed with strain L6 also resulted in seedlings with decreased root dry weights compared with uninoculated controls 13 weeks after sowing, but the significant inhibition of root growth was not apparent 26 weeks after sowing. Douglasfir seedlings originating from L5-inoculated seed had significantly lower root and shoot dry weights compared with uninoculated controls 13 but not 26 weeks after sowing. Inoculation of Douglas-fir seed with strain L6 resulted in seedlings with decreased root collar diameters and shoot dry weights 13 weeks after sowing, and lower root dry weights 26 weeks after sowing compared with uninoculated controls. These results demonstrate that the effects of bacterial inoculation on seedling emergence and on plant growth are independent, and that emergence-stimulating bacteria may inhibit subsequent seedling growth.     

Possible influence of Rhizobium on VA mycorrhiza metabolic activity in double symbiosis of alfalfa plants (Medicago sativa L.) grown in a pot experiment

Summary Alfalfa (Medicago sativa, L. cv Aragón) plants were grown under greenhouse conditions in pots of inert sand and vermiculite. The plants were inoculated with Rhizobium meliloti strain 102F28, with Glomus fasciculatus or with a mixture of both microorganisms. Plants inoculated with both Rhizobium and Glomus had the highest shoot dry weight and the lowest root-to-shoot ratio. Roots from dually inoculated plants also had a higher oxygen uptake and nodule nitrogenase activity than those from plants inoculated with either of the two microsymbionts alone. However, the dry weight of the roots from only VAM-infected plants was higher than those from Rhizobium or from Rhizobium plus Glomus-inoculated ones. These differences did not correlate with succinate dehydrogenase activity, which was similar between treatments. Nutrient element concentrations were increased in dually infected plants in comparison with those of plants inoculated with only Rhizobium or Glomus. These data suggest that Rhizobium may affect fungal metabolism and that the effect is not achieved via the tricarboxylic acid pathway.     

Molecular characterization and PCR detection of a nitrogen-fixing Pseudomonas strain promoting rice growth

Nitrogen-fixing plant growth-promoting rhizobacteria (PGPR) from the genus Pseudomonas have received little attention so far. In the present study, a nitrogen-fixing phytohormone-producing bacterial isolate from kallar grass (strain K1) was identified as Pseudomonas sp. by rrs (16S ribosomal RNA gene) sequence analysis. rrs identity level was high with an uncharacterized marine bacterium (99%), Pseudomonas sp. PCP2 (98%), uncultured bacteria (98%), and Pseudomonas alcaligenes (97%). Partial nifH gene amplified from strain K1 showed 93% and 91% sequence similarities to those of Azotobacter chroococcum and Pseudomonas stutzeri, respectively. The effect of Pseudomonas strain K1 on rice varieties Super Basmati and Basmati 385 was compared with those of three non-Pseudomonas nitrogen-fixing PGPR (Azospirillum brasilense strain Wb3, Azospirillum lipoferum strain N4 and Zoogloea strain Ky1) used as single-strain inoculants. Pseudomonas sp. K1 was detected in the rhizosphere of inoculated plants by enrichment culture in nitrogen-free growth medium, which was followed by observation under the microscope as well as by PCR using a rrs-specific primer. For both rice varieties, an increase in shoot biomass and/or grain yield over that of noninoculated control plants was recorded in each inoculated treatment. The effect of Pseudomonas strain K1 on grain yield was comparable to those of A. brasilense Wb3 and Zoogloea sp. Ky1 for both rice varieties. These results show that nitrogen-fixing pseudomonads deserve attention as potential PGPR inoculants for rice.