Screening Of Phosphate-solubilizing Bacteria In Rhizosphere Soils Of Jujube And Its Phosphate Dissolving Mechanism

Originated in China, jujube is the unique species of fruit tree in our country. With the characteristics and advantages of drought resistance, barren resistance, wind resistance, salt resistance, high yield and suitable for large area development, jujube has become a leading industry to increase farmers’ income and promote the development of the Xinjiang Uygur Auonomous Region’s economic. Whereas, as the increasing use of the chemical fertilizer in the field, its negative effects become more and more visible. The research of exploring a new kind of fertilizer source especially the issue of using the biological fertilizer completely or partly replace chemical fertilizer are greatly concerned.This study was conducted to explore the separation of phosphorus bacteria, screen and indentify rDNA 16 S of phosphorus bacteria from the rhizosphere soil, and study its phosphate Dissolving Mechanism on the base of rhizosphere soil in the important production areas in Xin Jiang Uygur Auonomous Region.The main results are as follows:1. four years born Jun zao microbial populations in the rhizosphere soil is higher than Junzao of eight. According to the rhizosphere bacteria on the growth, the amount of rhizosphere bacteria of eight years Junzao is higher than the root grows bacteria of four years, it shows certain differences in different kinds of bacteria. The amount and type of jujube rhizosphere bacteria is associated with rhizosphere soil nutrient, the content of available phosphorus in rhizosphere soil affects the distribution of nitrogen and inorganic phosphorus bacteria, the number of bacteria is closely related to the content of soil alkaline hydrolysisn, the correlation coefficient of between 0.85 and 0.94 respectively in（r=0.8）.2.Phosphate-solubilizing bacteria were screened from rhizosphere soils by using phosphate-solubilizing circle and molybdenum stibium anti-color methods. The 16 S rDNA of phosphate-solubilizing bacteria was sequenced and searched the public database by Blast, and then identify the species of phosphorus bacteria. The 20 strains belong to four genus bacteria: the Bacillus sp.、Acinetobacter sp.、Pseudomonas sp.、and Enterobacter sp.3.In Ca₃（PO₄）₂ solution containing, Strain P7, P13 were the most effective factors in dissolving phosphorus. After four days of incubation,its phosphate solubilizing capacity reached more than 300 μg/m L. This result shows that the amounts of dissolved phosphorus and the final pH values was in extremely significant negative correlation.4.In PVK solution containing, only 3 strains showed significant phosphorus-solubilizing effects, P3, P7, P9 were the most effective strains in dissolving phosphorus. It shows that the amounts of dissolved phosphorus and the final pH values was in extremely significant negative correlation.5. The 20 strains have different degrees of degradation ability to calcium phosphate and aluminum phosphate, and the effect of the strain P7 and P13 on the degradation ability of calcium phosphate was relatively good. The 20 strains are poor in degrading phytic acid calcium and iron phosphate.6. The amount and type of organic acids play an important role in the dissolution of inorganic phosphorus, and the effect of the acetic acid, the pyruvic acid and the butyric acid is the best. There are differences in the strains’ adaptability to the pH environment, such as the P7 is well adapted to alkaline environment, while P13 shows a preferences to acid environment. In the solution of inorganic phosphorus, the fermented liquid of acid phosphatase takes a predominant advantage, while alkaline phosphatase plays a dominant role in the degradation of organophosphorus.7. Using bacteria to improve the content of soil nitrogen, increase the content of available phosphorus in soil, increase soil organic matter content and lower the soil pH value. However, single bacteria plays a role in only one or two aspects of the work, and the effect of inoculums is greatly influenced by environment. Phosphate solubilizing bacteria can improve the fruit quality, especially the content of sugars, acids and Vc.