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

摘要

[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150．40～268．20μg／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12．09～22．16μg／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。%[Objective] The study aimed to isolate and screen efficient phosphorus-sol- ubilizing 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 dissolv- ing 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 se- lected strains differed significantly and tended to be volatile from 150.40 to 268.20 μg/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 se- cretion was from 12.09 to 22.16 μg/ml; the selected strains all could produce alka- line 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 signifi- cantly. [Conclusion] The study laid the foundation for relieving phosphorus in unpro- ductive land, saving phosphate resources, reducing environmental pollution and pro- viding fertilizer in alfalfa production.