Phosphorus solubilizing capability, IAA secretion and characteristics of phosphorus-solubilizing bacteria in rhizosphere of alfalfa in Guizhou Province | 贵州紫花苜蓿根际溶磷菌溶磷能力、分泌IAA及菌株特性研究

Chinese. [目的]分离筛选贵州紫花苜蓿根际高效溶磷菌株，探索其促生机理。[方法]采用无机磷和有机磷培养基，从贵州省种植的紫花苜蓿根际分离具有溶磷能力的菌株，通过溶磷圈法筛选解磷能力较强的菌株，并对其进行深入研究，同时，利用钼蓝比色法对菌株在液体培养条件下的溶磷能力进行测定。[结果]筛选的11株菌株分解磷酸钙的能力差异较大，溶磷量在150.40~268.20 ug/ml之间，各菌株的溶磷量与分泌有机酸量、培养介质pH之间均不存在显著相关性；各菌株均具有分泌IAA的能力，分泌量在12.09~22.16 ug/ml之间，分离的菌株均为产碱菌，大多数菌株菌落呈灰白色或乳白色、不规则、不透明、边缘不整齐、扁平、无色素；不同的菌株对碳源的利用存在着差异。[结论]该研究为缓解贵州地区贫瘠土地磷素供给、节约磷矿资源、降低环境污染以及生产苜蓿绿色产品提供肥料奠定了基础。

English. [Objective] The study aimed to isolate and screen efficient phosphorus-solubilizing strains from the root soil of alfalfa in Guizhou, and investigate its growth promoting mechanism. [Method] Phosphorus solubilizing bacteria were isolated from rhizosphere of alfalfa with inorganic and organic phosphorous medium and the strains with higher capacity of dissolving phosphorus were screened through dissolving phosphate zone and further researched. Meanwhile the phosphorus solubilizing capability of strains cultured in liquid medium was investigated by molybdenum blue colorimetric method. [Result] The capacity of dissolving calcium phosphate of 11 selected strains differed significantly and tended to be volatile from 150.40 to 268.20 ug/ml; phosphate solubilization capacity, IAA secretion and the pH of culture media did not show any significant correlation; all strains could produce IAA, and the secretion was from 12.09 to 22.16 ug/ml; the selected strains all could produce alkaline matter, and most of colonies were pale or milky white, irregular, opaque, jagged, flat and non-pigmented; utilization of carbon sources by different strains varied significantly. [Conclusion] The study laid the foundation for relieving phosphorus in unproductive land, saving phosphate resources, reducing environmental pollution and providing fertilizer in alfalfa production.