Study On The Effects Of Phosphate-dissolving Endophyte From Wheat

Phosphorus is one of the most important nutrients for plants’ growth. Althoughthere are lots of phosphorus in nature. but from the physicochemical characteristics,most of them are in organic or inorganic insoluble phosphorus that can not to beabsorbed directly by plants. Thus, high-yield crops still need to rely on a great deal ofphosphate fertilizers at this stage in our country. However, according to the practicalsituation at present, the application of P-fertilizers in cropland is always combined withvarious of metallic ions to form insoluble phosphorus. long-term application may notonly reduce the efficiency of fertilizers, but also may result in lots of environmentalpollution.Endophytic bacteria in most plants have growth-promoting effects on host plants,most of them are phosphate-dissolving bacteria. It is important and profound to studythis endophytic bacteria with the ability of dissolving phosphorus for increasing thecontent of effective phosphorus nutrition in the soil, improving wheat and otheragricultural products yields, decreasing the use of chemical fertilizers in the fields, andprotecting the ecological environment, etc. The main purpose of this study is to studythe influences of the ability of dissolving phosphorus under the multi-environmentfactors and to identify the strains with best effects of dissolving phosphorus on the basisof screening the endogenous strains of wheat with high efficiency ofphosphate-dissolving bacteria. Total31stains with stable ability ofphosphate-dissolving containing17strains from roots,11strains from stems and3strains from leaves were screened by preliminary screening. Then8stains with strongability of phosphate-dissolving were separated after rescreening, and the most powerfulphosphate-dissolving was the strain G2-19. The characteristic morphology, physiological and biochemical analysis and16SrDNA series analysis showed thatG2-19belonged to Bacillus brevis strain.Through changing different media and culture conditions and comparing thephosphate-dissolving ability of each strain, the study indicated that the ability ofdissolving the three common insoluble phosphates （Ca₃（PO_4）2, FePO₄and AlPO₄） ofG2-19is the strongest among all of screening strains,and under the three commonpesticides（40%Rogor,10%Glyphosate and20%Triadimefon） in the fields, the ability ofphosphate-dissolving of G2-19is also the strongest among all of screening strains.Many single factor experiments and orthogonality experiments showed that the effectsof phosphate-dissolving of G2-19is strongest when the carbon source is provided fromsaccharose, the nitrogen source is from ammonia sulfate, the content of phosphate is7g/L,the temperature is35degrees Celsius and the PH is8.