牡丹根际溶磷放线菌的筛选及其溶磷特性

通过从牡丹根际土壤中分离筛选溶磷放线菌,得到一株具有较强溶磷能力的菌株PSPSA1,根据形态特征、生理生化特性以及16S rDNA序列分析对菌株进行鉴定,并研究其溶磷遗传稳定性及溶磷特性.菌株PSPSA1被鉴定为白网链霉菌,具有较好的溶磷遗传稳定性.在不同磷源培养液中溶磷量依次为磷酸钙(158.5 mg·L^-1)>磷酸铝(139.9 mg·L^-1)>磷酸铁(127.7 mg·L^-1)>卵磷脂(45.6 mg·L^-1),在无机磷培养液中的溶磷量均与pH呈现显著负相关性,在有机磷培养液中的溶磷量与pH没有显著相关性.在不同碳源条件下的溶磷量依次为乳糖>葡糖糖>麦芽糖>果糖>蔗糖>淀粉>纤维素,在不同氮源条件下的溶磷量依次为蛋白胨>硝酸铵>硫酸铵>硝酸钾>尿素,以葡萄糖为碳源、蛋白胨为氮源时,菌株的溶磷量最高可达202.6 mg·L^-1.土培60 d,单施菌株土壤有效磷含量比对照增加68.2%,菌株与有机肥混施土壤有效磷含量比单施有机肥增加76.7%.表明菌株PSPSA1能够溶解多种难溶磷,在土壤中溶磷效果显著,与有机肥混施其溶磷能力明显提高,有望成为高效生物磷肥的优良菌种.

Screening and phosphate-solubilizing characteristics of phosphate-solubilizing actinomycetes in rhizosphere of tree peony.

A strain PSPSA1 with strong phosphate-solubilizing ability was isolated from the rhi-zosphere of tree peony. This strain was identified based on morphological characteristics, physiological and biochemical experiments, and 16S rDNA sequence analysis. Furthermore, its genetic stabi-lity and phosphate-solubilizing characteristics were investigated. Strain PSPSA1 was identified as the actinomycete Streptomyces albireticuli and showed high genetic stability. The order of phosphate solubilization capacity (PSC) in different phosphorus-source culture media was calcium phosphate (158.5 mg·L^-1) > aluminum phosphate (139.9 mg·L^-1) > ferric phosphate (127.7 mg·L^-1) > lecithin (45.6 mg·L^-1). The PSC and pH were significantly negatively correlated in inorganic phosphorus solution, but were not correlated in organic phosphorus solution. When using different carbon sources, PSC was in the order of lactose > glucose > maltose > fructose > sucrose > starch > cellulose. For different nitrogen sources, PSC was in the order of peptone > ammonium nitrate > ammonium sulfate > potassium nitrate > urea. Using glucose as a carbon source and peptone as a nitrogen source, strain PSPSA1 achieved the highest PSC of 202.6 mg·L^-1. After incubated for 60 days, the available phosphorus content in soil with a single application of strain PSPSA1 increased by 68.2% compared with control, and the available phosphorus content in soil with mixed application of strain PSPSA1 and organic fertilizer increased by 76.7% compared with a single application of organic fertilizer. The results indicated that the strain PSPSA1 had a strong ability to dissolve insoluble phosphorus and its mixed application with organic fertilizer improved the phosphorus solubilization. Thus, PSPSA1 is a promising microbial resource for the production of high-efficiency biological phosphorus fertilizer.