氧化尾矿与白茅根际尾矿中可培养溶磷菌比较研究

Comparison of Phosphate-solubilizing Bacteria from Oxidized Tailings and Rhizosphere Tailings of Imperata Cylindrica

溶磷菌是根际促生菌类群中重要组成部分,它转化的磷成为植物生长所需的重要磷源。研究分别从氧化尾矿和白茅根际尾矿中筛选溶磷菌,采用DNA分子技术确定它们的分类地位,并比较它们的溶磷能力和培养液pH的降低值。结果表明,白茅根际尾矿中筛选出的溶磷菌在数量和种类上均多于氧化尾矿,白茅根际尾矿中的筛选的溶磷菌具有更高的溶磷能力,放线菌门溶磷菌的溶磷能力显著低于其他类群的溶磷细菌。白茅根际尾矿中筛选出的隶属于伯克氏菌属的菌株N5-4溶磷能力最强,溶磷量达到536.40 mg L^(-1)。培养过程中,所有溶磷菌培养液的pH均有所降低,除放线菌门的微生物外,培养液pH降低值与溶磷菌的溶磷量存在着显著的正相关性(P<0.01,R=0.76)。

Phosphate-solubilizing bacteria （PSB） are vital groups of plant growth promoting rhizobacteria （PGPR）, and the soluble phosphate converted by PSB couldbecome an important phosphorus source for plant growth. In this study, PSB wasisolated from the oxidized tailings and rhizosphere tailings of Imperata cylindrica, the DNA molecular technology were used to determine the taxonomic status of PSB, and the phosphate-solubilizing capacity and the pH decline of culture medium were compared in order to reveal their relationship. Results showed that the quantities and the species of PSB isolated from rhizosphere tailings of Imperata cylindrica were more than those isolated from oxidized tailings. And PSB derived from rhizosphere tailings of Imperata cylindrica had higher phosphate-solubilizing capacity. Isolate N5-4, belonging to the genus Burkholderia spp., was isolated from rhizosphere tailings of Imperata cylindrica and showed the highest phosphate solubilization of 536.40 mg L^-1. However, the PSB of Actinobacteria showed significantly lower phosphate-solubilizing capacity than the other groups.The pH values of culture medium were all dropped during the process of culture. The phosphate-solubilizing capacity of all thegroups （except for PSB of Actinobacteria） showed positive correlation with the pH reduction of culture medium （P 〈 0.01, R = 0.764）.