中文摘要：

为了研究溶磷菌的溶磷机理,探究溶磷菌分泌有机酸的种类和数量与溶磷能力的相关性。利用PKO无机磷液体培养基对筛选自兰州周边的苜蓿（Medicago sativa）、白三叶（Trifolium repens）和红三叶（Trifolium pratense）根际的6株溶磷菌进行液体培养,采用钼蓝比色法和高效液相色谱法测定溶磷量及分泌有机酸的种类和数量。结果表明,各菌株溶磷量差异显著（P〈0.01）,有效磷增量在106.53--373.44 mg·L-1之间。供试菌株分泌有机酸的种类主要有草酸、酒石酸、苹果酸、乳酸、乙酸、柠檬酸和丁二酸等,但分泌有机酸的种类和数量差异较大。溶磷菌的溶磷量与总有机酸量间存在一定相关性,但有效磷增量并不完全由总有机酸量来决定,有机酸的种类和数量对溶磷量也有一定的影响,各种有机酸对溶磷量的影响程度和作用机理有待进一步研究。

英文摘要：

In order to investigate the phosphorus solubilizing mechanism of phosphate solubilizing bacteria,the relationship between phosphate solubilization ability and the category of organic acid produced by phosphate solubilizing bacteria was investigated.Six phosphate solubilizing bacteria screened from rhizosphere of Medicago sativa,Tri folium repens,and Tri folium pratense around Lanzhou area were cultured using PKO inorganic phosphorus liquid media.The phosphate solubilizing capacity and category of organic acids produced by bacteria were checked by means of molybdenum blue colorimetry and HPLC,respectively.The results showed that the phosphate solubilizing capacity of each bacteria presented significant difference（P0.01） and the increment of effective phosphate was between 106.53 ∽373.44 mg·L-1.The category of organic acids produced by phosphorus solubilizing bacterial included oxalic acid,tartaric acid,malic acid,lactic acid,acetic acid,citric acid,succinic acid and so on.However,the category and quantity of organic acids secreted by different strains had significant difference.Relativity was discovered between phosphate solubilizing capacity and total organic acids.The increment of effective phosphate was not entirely affected by total organic acid,and phosphate solubilizing capacity was affected by category and quantity of organic acids.Nonetheless,the influence degree and mechanism of organic acids effected phosphate solubilizing ability still needs further investigation.