本文選題：豆科牧草 + 促生菌(PGPR)��； 參考：《甘肅農業(yè)大學》2015年碩士論文

【摘要】：為收集豆科牧草優(yōu)良菌種資源,為后續(xù)生物接種劑(菌肥)研制提供優(yōu)質菌源,本研究利用鉬藍比色法和高效液相色譜法,以紫花苜蓿(Medicago sativa)、扁蓿豆(Trigonella ruthenica)、箭{H豌豆(Vicia sativa)、鷹嘴豆(Cicer arietinum)、小冠花(Coronilla varia)、鬼見錦雞兒(Caragana jubata)、黃芪(Astragalus membranaceus)、毛苕子(Vicia villosa)、甘草(Glycyrrhiza uralensis)等9種豆科牧草為研究對象,從其根系及根際土壤分離、篩選根際促生菌(PGPR),測定菌株溶磷和分泌植物激素(生長素和赤霉素)特性,并利用乙炔還原法測定了扁蓿豆、箭{H豌豆、小冠花、毛苕子和黃芪5種植物根瘤的固氮酶活性,同時利用細菌形態(tài)、生理生化特性及16S rDNA序列分析對篩選出的優(yōu)良促生菌株進行分類鑒定,主要結果如下:(1)從9種植物根際獲得溶無機磷菌株分離物167個,根瘤菌5個,經過溶磷能力初步篩選,得到具有溶磷特性菌株66株,其溶磷量在1.3μg·mL-1~574.4μg·mL-1之間,溶磷量最大的是分離自鷹嘴豆根際的菌株PYRS6。各菌株溶磷能力差異顯著(P㩳0.05),溶磷菌株的溶磷量與其培養(yǎng)液pH值之間具有一定的相關性,有5種植物根際溶磷菌株的溶磷量與其培養(yǎng)液pH值之間呈現(xiàn)極顯著負相關性(P0.01)。與參比菌株Azotobacter beijerinckii相比,本次分離的菌株有75.8%的溶磷量優(yōu)于參比菌株。(2)66株溶解無機磷菌株分泌植物激素的能力各不相同,其中,供試菌株分泌IAA量在2.09~43.3μg·mL-1之間,能力最強的菌株為PBRS5,分泌GA量在1.02~30.34μg·mL-1之間,分泌GA量最高的為PGRP9,并且有7株菌既具有分泌IAA能力,也兼具分泌GA的能力,其中以分離自鬼見錦雞兒和毛苕子根際的菌株PGRP9、PGRS4和PMRS4表現(xiàn)較佳。(3)5種豆科牧草根瘤的固氮酶活性在1.21 umolC2h4/g·h~11.87 umolC2h4/g·h之間,根瘤固氮酶活性大小依次為:M-GL㧐B-GL㧐J-GL㧐X-GL㧐H-GL。(4)通過細菌形態(tài)觀察、生理生化特定測定與分子生物學相結合的方法對15株優(yōu)良PGPR(包括5株根瘤菌)進行分類鑒定,溶磷菌分屬于6個屬,分別為假單胞菌屬、腸桿菌屬、芽孢桿菌屬、氮單胞菌屬、固氮菌屬以及克雷伯氏菌屬,共8個種,即:Pseudomonas fluorescens、Enterobacter cloacae、bacillus subtilis、Azomonas agilis、Bacillus megaterium、Azotobacter chroococcum、Azotobacter vinelandii、Klebsiella oxytoca;4株根瘤菌分屬于2個屬,為慢生根瘤菌屬和根瘤菌屬。
[Abstract]:In this study, molybdenum blue colorimetry and high performance liquid chromatography (HPLC) were used to collect the fine strain resources of legume forage grass and to provide high quality bacteria source for the subsequent development of biological inoculants (bacterial fertilizer).Phytohormone and growth hormone (auxin and gibberellin) were determined, and the nitrogenase activities were determined by acetylene reduction method in five plant rhizobia, I. e., Astragalus root nodule, Astragalus membranaceus and Astragalus membranaceus, and the activity of nitrogenase was determined by acetylene reduction method, such as Astragalus membranaceus and Astragalus membranaceus.At the same time, the bacteria morphology, physiological and biochemical characteristics and 16s rDNA sequence analysis were used to classify and identify the excellent growth-promoting strains. The main results were as follows: 1) 167 isolates of soluble inorganic phosphorus and 5 rhizobia were obtained from the rhizosphere of 9 species of plants.After preliminary screening, 66 strains with the characteristic of phosphorus solubilization were obtained. The phosphorus soluble amount was between 1.3 渭 g mL-1~574.4 渭 g mL-1 and PYRS6, which was the highest in the rhizosphere of chickpea.There was a significant difference in phosphorus solubilization ability of each strain (P < 0.05). There was a certain correlation between phosphorus solubilization and pH value of the culture medium, and there was a very significant negative correlation between phosphorus solubilization and pH value in the culture solution of five plant rhizosphere strains.Compared with the reference strain Azotobacter beijerinckii, 75.8% of the strains were superior to the reference strain. The ability of dissolving inorganic phosphorus from 66 strains was different. Among them, the amount of IAA secreted by the tested strains was between 2.09 and 43.3 渭 g mL-1.The most potent strain was PBRS5, which secreted GA between 1.02g and 30.34 渭 g mL-1, and the highest amount of GA was PGRP9. There were 7 strains with both the ability to secrete IAA and the ability to secrete GA.Fifteen excellent PGPRs (including 5 rhizobia) were classified and identified by combining physiological and biochemical methods with molecular biology. Phosphorolytic bacteria belong to 6 genera, namely Pseudomonas, Enterobacter, Bacillus, Amonomonas.
【學位授予單位】：甘肅農業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：S54;S182

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