中文摘要：

【目的】体外促生能力是衡量微生物菌株作用的一个重要指标,测定获取的植物根际促生菌并明确其对披碱草的促生效果,可为其在生产中的应用提供依据。【方法】2014年9月从西藏阿里地区采集披碱草根系及根际土壤,以常规方法分离出其中的溶磷菌、固氮菌和分泌3-吲哚乙酸（IAA）细菌的10株菌株。测定其溶磷量、固氮酶活性及分泌生长素能力,并将其制成植物根际接种剂,测定接种剂对披碱草生长的影响及其在根际的定殖能力。【结果】菌株PWXZ10溶磷能力较好,达40.89 mg/L;菌株003PWXZ6固氮酶活性较强,达421.21 nmol/（m L·h）;菌株NXP17分泌生长素能力较强,达31.33μg/m L。与对照菌株（Pseudomonas sp.Jm92）相比,菌株003PWXZ6和NXP17制备的接种剂可显著增加披碱草株高、地上生物量和地下生物量（P〈0.05）,但两者之间差异不显著（P〉0.05）;接种剂003PWXZ6对披碱草根总长、根表面积、根体积、根直径、含磷量、含氮量和粗蛋白含量增加显著（P〈0.05）,分别较对照菌株（Pseudomonas sp.Jm92）增加了330%、199%、118%、187%、70%、15%和19%,并且该菌株在根际定殖能力很强。【结论】植物根际促生菌003PWXZ6和NXP17对披碱草具有良好促生效果,可为开发经济环保的生物肥料提供了菌种资源。

英文摘要：

【Objectives 】 The ability of external growth promotion is an important indicator to measure the microbiological strain. To measure the selected plant growth promoting rhizobacteria and clarify their promoting growth efficiency to Elymus dahuricus can provide the basis for the application in production.【Methods】The root morphology of Elymus dahuricus and rhizosphere soil were collected from Ali Region of Tibet in September 2014.Ten rhizobacteria strains,which could dissolve P,fix N and excrete 3- indole acetic acid（ IAA） were isolated from root and rhizosphere soil with the conventional separation method of bacteria. The capacity of dissolving P and excreting IAA,the activity of fixing N in rhizosphere were investigated,and the effect of rhizobacteria inoculants on the growth of Elymus dahuricus were assessed. 【Results 】 Strains PWXZ10,003PWXZ6,NXP17 showed the strongest phosphate solubilizing capacity（40. 89 mg / L）,nitrogenase activity [421. 21 nmol /（ m L·h）],and IAA secreting ability（ 31. 33 μg / m L）,respectively. Compared with the control strains Pseudomonas sp. Jm92,inoculum 003PWXZ6 and NXP17 significantly increased plant height,aboveground biomass and underground biomass（ P 0. 05）,but the increase effects were not significantly different between the two strains（ P 0. 05）.In addition, inoculum 003PWXZ6 significantly increased root length, root surface area, root volume, root diameter,phosphorus content,containing nitrogen and crude protein content（ P 0. 05）. Compared with the control strains Pseudomonas sp. Jm92,above items were improved by 330%,199%,118%,187%,70%,15%,and 19%,respectively,showing the strongest colonization ability in the rhizosphere.【Conclusions】These results suggest that strains 003PWXZ6 and NXP17 has the best growth promoting effect to Elymus dahuricus among the strains. Therefore the strain resources is potential for the development of economy and environmental protection.