溶磷菌株组合的溶磷效应及对玉米生长的影响

【目的】 本研究以革兰氏阴性菌Pseudomonas fluorescens CHA0、F113、Phl1c2、PF5与阳性菌Bacillus megaterium X14为研究对象，通过各菌株及菌株组合的溶磷能力评判组合效果，并进一步通过玉米盆栽试验验证其应用效果。【方法】 通过菌株在NBRIP培养基中对难溶磷源Ca₃（PO₄）₂的溶解能力评价各菌株及菌株组合的溶磷能力，测量接菌处理后的玉米干重、株高和全磷含量评价各菌株和菌株组合的盆栽应用效果。【结果】 1）纯培养实验中CHA0、F113、Phl1c2、PF5在NBRIP无机磷液体培养基中可溶磷含量均显著高于X14，且4株阴性菌两两组合后，培养基中可溶磷含量显著高于对应的阴性菌与阳性菌的组合，即阴性菌组合后的溶磷效果高于阴性菌与阳性菌组合后的溶磷效果。2）单菌比较，盆栽试验接种阳性菌X14对玉米生长及全磷吸收累积量的效果与阴性菌的差异不及室内实验显著，说明该阳性菌盆栽应用效果较好。比较菌株组合的处理，发现接种阴性菌与阳性菌组合的处理，其对玉米生长及全磷吸收累积量的效果与接种对应的阴性菌组合的处理效果相近，甚至显著高于一些阴性菌组合。3）综合比较室内实验结果与盆栽试验结果，发现阳性菌X14虽然在培养基中溶磷效果差，但在盆栽试验中，无论是单菌还是与阴性菌组合后的处理均表现出了良好的溶磷效果，且部分阴性菌与该阳性菌配合后，在玉米盆栽应用中促生和溶磷效果最佳。【结论】 与阴性菌组合相比，阳性菌与阴性菌组合室内溶磷效果均较差，但盆栽应用效果良好，甚至优于部分阴性菌组合，表明筛选溶磷菌株组合时，单一的室内纯培养结果不能作为唯一的评价指标，应同时结合盆栽的促生及溶磷效果。

Dissolving capacity of phosphate dissolving bacteria strains combination and their effects on corn growth

[Objectives] This study choose 4 different strains of Pseudomonasfluorescens (gram-negative bacteria),respectively as CHA0,F113,Phl1 c2 and PF5,and one gram-positive bacterium,Bacillus megaterium X14,as phosphate solubilizing bacteria (PSB) to verify how bacteria helps dissolving phosphate to improve the growth of corn.[Methods] Soluble phosphate content in each single and double strains of PSB incubated solution was measured to compare the solubization of each strain and combination.Dry weight,height and total phosphorus content of potted corn samples were examined to evaluate the solvency rate of insoluble phosphorus source Ca3(PO4)2 and colonization of different single and double strains PSB solution.[Results] 1) Under NBRIP broth growth condition,after single strain inoculated,any of the 4 G-bacteria (Pseudomonas fluorescens CHA0,F113,Phl1c2,PF5) solution dissolved much more phosphate than G+ bacteria (Bacillus megaterium X14).The combination of any two G-bacteria solution showed higher phosphate dissolving than combination with any one G-bacterium and the G+ bacterium combination.2) There were no significant differences of phosphate solubilizing and plant healthy if corn growth in pot under greenhouse,regardless which single strain was inoculated.3) The corn inoculated with a double strains with the G+ bacteria (Bacillus megaterium X14) and any one of the G-bacteria (Pseudomonas fluorescen) strains showed higher phosphate absorption and more healthy growth than any of 2 G-bacteria strains combination.[Conclusions] In conclusion,G+ and G-bacteria combination inoculation helps to absorb more phosphate in potted corn growth even the same solution showed less effective to dissolved phosphate in laboratory NBRIP condition.The laboratory absorption experiment should not be the only indicator to select PSB strains.Consideration of both laboratory absorption and potted growth experiments should provide more information for application.