兰州地区苜蓿和红豆草根际溶磷菌筛选及菌株部分特性研究

Isolation and Characteristics of Phosphorus-solubilizing Bacteria in Rhizosphere of Alfalfa and Sainfoin in Lanzhou

利用溶磷圈法对苜蓿和红豆草根际不同部位溶磷细菌进行了分离,共获得分离物386个,其中137个具有溶磷能力。苜蓿和红豆草根际不同部位溶磷菌数量分布有差异,其数量为RS>RP>NRS>HP。对筛选获得的12株溶磷圈较大的菌株进行菌落形态特征观察发现,大多数菌落呈灰白色或乳白色、不规则、半透明、边缘不整齐、突起、无光泽、无色素。进一步利用钼蓝比色法对菌株分解磷矿粉能力测定显示,各菌株分解磷矿粉能力差异较大,溶磷量最大为338.4mg/ml,最小为25.9mg/ml,这与其自身溶磷机制有关。溶磷量与菌株培养液pH值之间存在显著相关性。12株菌株大部分具有分泌IAA的能力,其中LM6和LH9分泌IAA能力较强。

Isolation and characteristics of phosphorus-solubilizing bacteria in rhizosphere of alfalfa and sainfoin were studied. 386 phosphobacteria strains were obtained, and among them, 137 strains showed higher phosphorus-solubilizing activity. There was different amount of phosphate-dissolving microorganisms in different section of the plant rhizosphere, the amount in different section was in the order： RS 〉RP〉NRS〉HP. 12 stains were selected for morphological characteristics study, and majority bacterial colony was offwhite or milkiness, irregulart, translucent, processes, matt, non-pigment. Further study on phosphorus solubilizing capability of the strains with the molybdenum blue spectrophotometry indicated that there were great differences in phosphate-dissolving microorganisms＇ capability of dissolving rock phosphate, the maximum phosphate solubilization capacity was 338.4 mg/ml while the minimum was 25.9 mg/ml, which related to the mechanism of phosphate solubilization of the strains. There were obvious relationship between the phosphate solubilization capacity and the pH. Most of the strains had the ability to produce IAA, the strain LM6 and LH9 had the strongest ability to produce IAA.