枣根际解磷细菌解磷特性及影响因素分析

Characteristics and influencing factors of phosphate solubilizing bacteria in jujube rhizosphere

从pH值、微生物自身固持、磷酸酶活性和有机酸种类和数量等方面对从枣根际土壤中筛选出的4株解磷菌株进行解磷机理研究。结果表明:4株解磷菌株偏酸性条件有利于发酵液中可溶性磷的释放,在Ca_3(PO_4)_2培养基中,P7在酸性和中性条件下,6 d时可溶性磷质量浓度高达218.68~225.26 mg·L^(-1),而在碱性条件下,可溶性磷质量浓度仅77.57 mg·L^(-1),在PVK培养基中,P7和P13具有较强的解有机磷能力;菌株经灭活处理后基本上不存在解磷能力,菌体本身吸收利用了部分有效磷;在Ca_3(PO_4)_2培养基中,酸性磷酸酶活性要高于碱性磷酸酶活性,而在PVK培养基中结果与之相反;有机酸能够起到对磷的降解作用,尤其是对无机磷的降解,Bacillus sp.P3在Ca_3(PO_4)_2培养基中,有机酸主要是乳酸、乙酸、戊二酸和少量的丁二酸及柠檬酸,不同的菌株对环境pH值的敏感度不同。

Total 4 of solubilizing strains of phosphate solubilization bacteria were screened from jujube rhizosphere to study the phosphate solubilization mechanism based on the effects of pH,microbial activity,phosphatase activity,the type and quantity of organic acid.The results showed that 4 strains of phosphate solubilization bacteria were beneficial to the release of soluble phosphorus in fermentation broth with different media under acidic condition.In the Ca 3(PO 4)2 medium,the soluble phosphorus content of P7 reached 218.68~225.26 mg·L-1 at 6 d in acidic and neutral conditions.Under alkaline conditions,the soluble phosphorus content was only 77.57 mg·L-1.In the PVK medium,P7 and P13 had strong ability to hydrolyze organic phosphorus.After inactivation of the strains,they lost ability to dissolve phosphorus but the bacteria itself absorbed parts of the available phosphorus.In the Ca 3(PO 4)2 medium,the activity of acid phosphatase was higher than those of alkaline phosphatase.Nevertheless,the activity of acid phosphatase in PVK medium was lower than those of alkaline phosphatase.Organic acids could play an important role in the degradation of phosphorus,especially the degradation of inorganic phosphorus.In the Ca 3(PO 4)2 medium,Bacillus sp P3 were affected by organic acids mainly lactic acid,acetic acid,glutaric acid,a few of succinic acid and citric acid.The sensitive of strains to surrounding pH was totally different.