有机磷降解菌的筛选及其促生特性

【目的】从环境中筛选高效有机磷降解菌及研究其促生机制。【方法】利用蒙金娜有机磷培养基筛选有机磷降解菌,用生化实验对其促生特性进行研究,且通过盆栽实验筛选对黄瓜苗有促生作用的高效有机磷降解菌。【结果】从草坪根周筛选到35株有机磷降解菌,选择5株代表性菌进行黄瓜盆栽实验。结果表明G3-6有机磷降解能力最强,溶磷圈直径(HD)与菌落直径(CD)比值为3.28,且对黄瓜苗的促生效果优于其他菌株。与CK相比,G3-6可提高黄瓜苗鲜重71.53%、干重69.78%和株高33.55%;与阳性对照枯草芽孢杆菌F-H-1相比,G3-6可提高黄瓜苗鲜重2.52%、干重21.14%和株高8.27%。相关分析结果表明降解有机磷能力在促进植物生长过程中可能发挥着比其他功能更重要的作用。16S r RNA序列分析初步鉴定G3-6为假单胞菌属。【结论】假单胞菌G3-6除具有较强的有机磷降解、分泌IAA和铁载体能力,对黄瓜苗也有较好的促生作用,是1株潜在的具有广阔市场应用价值的高效促生菌。

Screening and growth promoting characteristics of efficient organophosphate-degradation bacteria

[Objective] Our aim is to screen efficient organophosphate-degradation bacteria from environment and study their growth promoting mechanism. [Methods] We screened organophosphate-degradation bacteria from environment using selective medium, and studied the promoting growth characteristics by biochemical assays, then screened organophosphate-degradation and plant-growth-promoting bacteria by pot experiment. [Results] In total 35 strains of organophosphate-degradation bacteria were isolated from bulk soil of grass by Mengjinna organophosphate-degradation medium. The promoting growth characteristics of these bacteria were checked by biochemical methods. Five representative strains were selected for cucumber seedlings pot experiment. Strain G3-6 had the strongest ability to solubilize organic phosphorus, the ratio of hydrolysis circle diameter (HD) and colony diameter (CD) was 3.28. Strain G3-6 had the highest ability to promote cucumber growth than other strains. Compared with the control, G3-6 increased fresh weight, dry weight and height of cucumber seedlings by 71.53%, 69.78% and 33.55%, respectively. Compared with the positive control Bacillus subtilis F-H-1, G3-6 increased fresh weight, dry weight and height of cucumber seedlings by 2.52%, 21.14% and 8.27%, respectively. The results of correlation analysis showed that the ability of organophosphate-degradation might play a more important role in promoting cucumber growth than other functions. Strain G3-6 was identified as Pseudomonas sp. by 16S rRNA analysis. [Conclusion] Pseudomonas sp. G3-6 has strong ability of depredating organic phosphate, and can strongly promote cucumber growth. This strain would be a potential growth promoting bacterium.