不同生存环境和磷酸盐对4株溶磷菌溶磷能力的影响

利用液体培养法研究了不同NaCl浓度、碳源、氮源、溶解氧及磷酸盐对分离自小麦(Triticum aestivum)、苜蓿(Medicago sativa)根际的4株优良溶磷细菌(Lx81、Jm92、Dm84、Lx191)溶磷能力的影响.结果表明:(1)4株溶磷菌均为高耐盐菌株,其中Jm92和Din84维持较高溶磷量的NaCl浓度最高阈值分别为4%和8%,Lx81、Lx191在NaCl浓度超过5%时溶磷活性受到抑制.(2)Lx81的最佳碳源是葡萄糖,其次为蔗糖;另外3株菌在葡萄糖和蔗糖为碳源时,均有较高的溶磷能力;4株菌都几乎不能利用淀粉.(3)Lx81和Jm92在以(NH_4)_2SO_4和NH_4 NO_3为氮源时溶磷活性均较高,(NH_4)_2SO_4 是Lx191的最佳氮源,而NH~+-N存在会导致Dm84溶磷活性降低.(4)供试4株菌均不是专性厌氧菌,但不同菌株对氧的需求量不同.(5)4株溶磷菌对Ca_3-P和Ca_8-P有较大的溶解效率,但它们几乎都不能溶解Ca_(10)-P.图3表4参14

Effects of Different Habitats and Insoluble Phosphates on Phosphate Solubilizing Activity of Four Phosphate Solubilizing Bacteria

The effects of different NaCl concentrations, carbon sources, nitrogen sources, dissolved oxygen and insoluble phosphates on phosphate solubilizing activity of four phosphate solubilizing bacterial (PSB) strains isolated from rhizosphere of wheat (Triticum aestivum) and alfalfa (Medicago sativa) were studied in liquid media. The results showed that the four isolates had high phosphate solubilizing capacity to tolerate salt stress. Strains Jm92 and Dm84 could tolerate NaCl at 4% and 8% concentrations, respectively, while strains Lx81 and Lx191 could tolerate NaCl at 5% concentrations. Lx 81 had the highest capacity to solubilize rock phosphate when supplied with glucose, and it was also able to use saccharose to solubilize rock phosphate. The other three strains had higher phosphate solubilization activities when supplied with glucose and saccharose, but all of them used a little starch to solubilize rockphosphate. Lx81 and Jm92 had stronger capacity to dissolve rock phosphate when supplied with (NH_4)_2SO_4 and NH_4NO_3, Lx191 showed strong ability to solubilize rock phosphate only at (NH_4)_2SO_4 medium. However, Dm84 decreased its activities for dissolving rock phosphate at NH_4~+-N medium. The four PSB strains were not obligate anaerobic bacteria, but different strains differed in requirements for O_2. All of them could readily solubilize Ca_3(PO_4)_2 and Ca_8H_2(PO_4)_6·H_2O phosphate. However, they almost could not solubilize (Ca_(10)(PO_4)· F_2 phosphate. Fig 3, Tab 4, Ref14