乳酸菌培养液中活菌数与吸光度的关系研究

通过平板计数法测定脱脂乳为培养基的发酵液中乳酸菌的活菌数,并测其对应的吸光度,研究两者之间的相关关系。结果表明:在发酵过程中以脱脂乳为培养基的发酵液中乳酸菌的活菌数与吸光度之间呈线性相关关系。因此,通过测定发酵液的吸光度可以评定发酵乳制品中乳酸菌的活菌数。     

新疆核桃根际土壤中解钾菌的分离筛选及鉴定

为给核桃专用微生物肥的研制提供菌株材料,通过对解钾菌的分离纯化,筛选对新疆核桃根际土壤具有解钾作用且能在其根际稳定定殖的优质高效菌株。结果表明:从阿克苏、和田、喀什3个新疆核桃主产区的根际土壤中分离出解钾菌27株;采用火焰光度计法对其解钾能力进行测定,选出解钾菌16株;经耐利福平诱导后剩余14株;将其进行大田定殖试验后,最终筛选出10株解钾能力较强的菌株。经16S r DNA进行鉴定,得出这10株解钾菌归属于3个属。分别为假单胞菌属Pseudomonas、芽孢杆菌属Bacillus、微杆菌属Microbacterium,其中假单胞菌属为优势种属。     

牛场肥水灌溉对土壤氨氧化微生物的影响

以不同牛场肥水灌溉制度下河北省徐水县梁家营长期定位施肥试验田为研究对象,通过构建氨氧化细菌和氨氧化古菌的amoA 基因克隆文库,利用T-RFLP方法研究了5种施肥处理(CK:不施肥;CF:300 kg N·hm^-2,120 kg P₂O·hm^-2,75 kg K₂O·hm^-2;T4:105 kg N·hm^-2,39 kg P₂O₅·hm^-2;T5:210 kg N·hm^-2,78 kg P₂O₅·hm^-2; T11:317 kg N·hm^-2,117 kg P₂O₅·hm^-2)下土壤中氨氧化细菌及氨氧化古菌的多样性及其群落结构演变。氨氧化细菌T-RFLP结果显示,T5 处理土壤中氨氧化细菌的 Shannon-Wiener指数(H')和 Pielou指数(E)均最高, T11处理最低,表明T5处理增加了土壤中氨氧化细菌的多样性和丰富度,T11处理一定程度上降低了氨氧化细菌的多样性和丰富度。基于amoA基因建立的系统进化树显示,土壤中氨氧化细菌主要属于Nitrosospira 和Nitrosomanas。氨氧化古菌T-RFLP结果显示,T11处理氨氧化古菌Shannon-Wiener指数(H')、Simpson 指数(Ds)和Pielou指数(E)均最高,表明T11处理增加了土壤中氨氧化古菌的多样性和丰富度。氨氧化古菌的系统发育树显示大部分氨氧化古菌amoA序列与 Cluster S 聚为一类,且占主导地位,少数序列为Unclassified-Archaea(未分类古菌)。最大优势菌与来自中国荷斯坦奶牛瘤胃样品的氨氧化古菌Clone属于同种,推测牛场肥水灌溉增加了土壤的氨氧化古菌的群落多样性。     

Responses of native legume desert trees used for reforestation in the Sonoran Desert to plant growth-promoting microorganisms in screen house

Three slow-growing legume trees used for desert reforestation and urban gardening in the Sonoran Desert of Northwestern Mexico and the Southwestern USA were evaluated whether their growth can be promoted by inoculation with plant growth-promoting bacteria (Azospirillum brasilense and Bacillus pumilus), unidentified arbuscular mycorrhizal (AM) fungi (mainly Glomus sp.), and supplementation with common compost under regular screenhouse cultivation common to these trees in nurseries. Mesquite amargo (Prosopis articulata) and yellow palo verde (Parkinsonia microphylla) had different positive responses to several of the parameters tested while blue palo verde (Parkinsonia florida) did not respond. Survival of all tree species was over 80% and survival of mesquite was almost 100% after 10 months of cultivation. Inoculation with growth-promoting microorganisms induced significant effects on the leaf gas exchange of these trees, measured as transpiration and diffusive resistance, when these trees were cultivated without water restrictions.     

PGPB对红树植物木榄幼苗的接种效应

通过盆栽试验研究了植物促生菌(PGPB)对红树植物木榄幼苗的接种效应,供试菌为6种解磷菌(即B.amy,Vib,B.atr,Xan,B.Lic,P.M.)和5种固氮菌(即Au4,Phy,24S,JA4,cd),结果表明:(1)分别接种6种解磷菌株6个月后木榄幼苗的生长均得到了不同程度的促进,与对照相比,木榄苗高增加21.57%～9.54%,生物量增加27.49%～20.32%,叶片的氮含量增加33.33%～1.35%,叶片的磷含量增加24.42%～2.04%;经差异显著性检验,B.amy和Vib 2个菌种对木榄幼苗的促生效应比其它解磷菌株更明显;(2)分别接种5种固氮菌株6个月后木榄幼苗的生长均得到了促进,与对照相比,木榄幼苗的均高增加24.07%～10.22%,生物量增加32.36%～19.71%,叶片的氮含量增加23.39%～4.05%,叶片的磷含量增加32.79%～4.99%;差异显著性检验表明:Au4和Phy 2个菌种对木榄幼苗的促生效果比其它固氮菌更显著.     

添加不同酵母培养物对瘤胃纤维分解菌群和纤维素酶活的影响

用3种酵母培养物(YC- 1、YC 2和YC- 3)分别饲喂4头带有永久性瘤胃瘘管的肉牛,研究培养物对瘤胃发酵、纤维分解酶活性和3种纤维分解菌数量的影响,结果表明:YC 2处理的乙酸、丙酸、丁酸和总 VFA浓度显著高于对照组(P<0 .05),YC 1和YC 3处理的乙酸/丙酸比例显著降低(P<0 .01);各处理均能显著提高瘤胃内羧甲基纤维素酶、水杨苷酶和木聚糖酶的活性(P<0 .01);各处理都显著提高黄化瘤胃球菌的相对比例(P<0 .01),16SrRNA特异性寡聚核苷酸探针杂交法分析测定结果表明 3 种纤维分解菌在瘤胃细菌中所占比例为 3. 80%±0 .2%。     

1株烟草青枯病拮抗内生细菌的分离及鉴定

为了筛选具有生防价值的拮抗烟草青枯雷尔氏菌的内生细菌,从湖南长沙、永州、郴州烟草青枯病发病区的健康烟株采集茎秆,采用稀释平板分离法获得150个内生菌株.抑菌结果表明,21个内生菌株对烟草青枯雷尔氏菌2316菌株有拮抗效果,占总菌株数的14.0％.拮抗菌株中,F1菌株24 h对烟草青枯雷尔氏菌株2316抑菌圈直径达6.5...     

Utilization of Sparingly Soluble Phosphate by Red Clover in Association with Glomus mosseae and Bacillus megaterium

A pot experiment was conducted to investigate the mobilization of sparingly soluble inorganic and organic sources of phosphorus (P) by red clover (Trifolium pratense L.) whose roots were colonized by the arbuscular mycorrhizal (AM) fungus Glomus mosseae and in association with the phosphate-solubilizing (PS) bacterium Bacillus megaterium ACCC10010. Phosphate-solubilizing bacteria and rock phosphate had a synergistic effect on the colonization of plant roots by the AM fungus. There was a positive interaction between the PS bacterium and the AM fungus in mobilization of rock phosphate, leading to improved plant P nutrition. In dual inoculation with the AM fungus and the PS bacterium, the main contribution to plant P nutrition was made by the AM fungus. Application of P to the low P soil increased phosphatase activity in the rhizosphere. Alkaline phosphatase activity was significantly promoted by inoculation with either the PS bacterium or the AM fungus.     

甜菜褐斑病内生拮抗菌的筛选、鉴定及其防效测定

 Three hundred and one endophytic bacteria strains were isolated from healthy sugar beet plants in severely diseased plots in Changji County,Xinjiang Province.Three endophytic bacteria strains,1-5,4-1 and 4-3,showed relatively strong antagonistic against Cercospora beticola.Strain 1-5 was identified as Paenibacillus polymyxa,while strains 4-1 and 4-3 were as Bacillus flexus and Stenotrophomonas sp. by their morphological,physiological and biochemical characteristics.The results from several experiment trials showed that the endophytic bacteria could reduce the disease incidence of sugar beet.The control efficiency reached from 67.6% to 80.2%, indicating that biocontrol with endophytic bacteria was an alternative and potential method to control sugar beet fungi disease.     

鱼稻共生条件下陶粒载体水稻浮床提高细菌活性及多样性

以轻质陶粒为主要原料开发出一种新型生物浮床载体,并通过种植水稻构建了陶粒载体水稻浮床对池塘水环境进行修复。研究了陶粒载体水稻浮床对精养池塘的水质净化作用,并采用Biolog-ECO技术分析了陶粒载体水稻浮床对池塘浮游细菌碳源代谢模式和多样性的影响。结果显示,试验组池塘水中总氮(TN)、总磷(TP)和亚硝态氮(NO2–-N)等水质指标在8月份显著低于对照组,高锰酸盐指数(IMn)在8月份和10月份显著低于对照组。试验组池塘浮游细菌群落代谢活性(AWCD)、Shannon指数和丰富度指数在8月份显著高于对照塘,Shannon均匀度指数在10月份显著高于对照塘。浮床种植水稻产量达到5 900 kg/hm~2。结果表明陶粒载体水稻浮床在具备一定生产性能基础上,降低了精养池塘水中氮磷营养水平,改变了精养池塘浮游细菌群落碳源利用模式,并提高了池塘浮游细菌群落代谢活性和功能多样性。结果可为应用陶粒载体水稻浮床调控池塘水环境提供理论指导。