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【目的】为了提高红壤磷素利用率,探讨溶磷菌溶磷机理。【方法】利用难溶性无机盐培养基从花生根际土壤样品中分离到一株溶磷菌C5-A,结合菌落形态特征、生理生化和16S rRNA序列确定该菌株的系统发育地位;通过菌株C5-A在NBRIP液体培养基培养过程中培养液pH变化确定其溶磷能力;利用液体发酵实验测定不同的碳源、氮源对菌株C5-A溶磷的影响;通过高效液相色谱检测C5-A在不同氮源培养液中有机酸的种类和浓度。【结果】菌株C5-A鉴定为洋葱伯克霍尔德氏菌(Burkholderia cepacia),遗传稳定性较好。在FePO4和AlPO4培养液中,菌株C5-A的溶磷量和pH变化呈显著负相关;菌株C5-A对磷酸三钙、磷酸铝、磷酸铁、磷矿粉均有较强的溶解能力,最高溶磷量分别为125.79、227.34、60.02和321.15 mg/L;菌株C5-A对不同浓度的两种磷矿粉有较强的溶解能力;分别以麦芽糖和草酸铵为碳源和氮源时溶磷量最高。高效液相色谱检测出10种有机酸,分别为草酸(葡萄糖酸)、乙酸、苹果酸、琥珀酸和5种未知有机酸,然而,乙酸而非草酸似乎是影响C5-A溶磷的重要有机酸。【结论】从红壤花生根际土壤中筛选到一株对难溶性无机盐具有较强溶解能力溶的菌株C5-A,有望为开发高效红壤微生物磷肥提供种质资源。
【Objective】 In order to improve the phosphorus utilization of red soil, the mechanism of phosphorus solubilization was discussed. 【Method】 A strain of phosphate-solubilizing bacteria C5-A was isolated from peanut rhizosphere soils by using sparingly soluble inorganic salt medium. The morphological, physiological, biochemical and 16S rRNA sequences of the colonies were used to determine the phylogenetic position of the strain. -A in the culture broth of NBRIP liquid medium to determine the change of pH of the culture solution; liquid fermentation experiments were used to determine the effect of different carbon and nitrogen sources on the phosphorus solubilization of the strain C5-A; HPLC- A in different nitrogen sources of organic acid culture medium and concentration. 【Result】 Strain C5-A was identified as Burkholderia cepacia, with good genetic stability. In FePO4 and AlPO4 medium, the amount of phosphate solubilizing of strain C5-A was negatively correlated with the change of pH. Strain C5-A had strong ability to dissolve tricalcium phosphate, aluminum phosphate, iron phosphate and phosphate rock, The maximum phosphorus solubilities were 125.79, 227.34, 60.02 and 321.15 mg / L, respectively. Strain C5-A had strong ability to dissolve two kinds of phosphate rock with different concentrations. When maltose and ammonium oxalate were used as carbon source and nitrogen source respectively, The highest amount of dissolved phosphorus. Eleven organic acids were detected by HPLC, namely oxalic acid, acetic acid, malic acid, succinic acid and five unknown organic acids. However, acetic acid rather than oxalic acid appears to be an important organic acid. 【Conclusion】 The strain C5-A, which has a strong ability to dissolve insoluble inorganic salts, was screened from the rhizosphere soils of red soil so as to provide germplasm resources for developing high-efficiency red soil microbial phosphate fertilizers.