Isolation Of Phosphate Solubilizing Bacteria From The Rhizosphere Of Wheat And Study On Efficiency Of Solubilizing Phosphate

Phosphorus is not only an important component of various substances in plants,but also participates in many metabolic reactions in plants and is a necessary nutrient for plant life activities.At present,the phosphorus in agricultural soil is mainly in the form of insoluble organic or inorganic compounds which is not easy to be used by plants,and the available phosphorus content is low,which is an important factor limiting agricultural production.The phosphate solubilizing microorganisms(PSM)are a major group in soil that can solubilize the insoluble phosphate compounds into soluble forms and increase the soluble phosphorus in soils.Therefore,the aim of this study is to screen phosphate-solubilizing bacteria with efficient ability to dissolve phosphorus and through the role of phosphate-solubilizing bacteria to slow down soil available phosphorus fixation rate,dissolve insoluble phosphorus and improve the soil available phosphorus content to meet the crop the demand for phosphorus.In this paper,at 28?,26 strains tricalcium phosphate phosphate-solubilizing bacteria,41strains hydroxyapatite phosphate-solubilizing bacteria and 113 strains calcium phytate phosphate-solubilizing bacteria were screened from the rhizosphere soil of wheat in Shandong Agricultural University Huantai wheat test base and Binzhou saline soil.Among them,two strains of phosphate-solubilizing bacteria,Q-13-3-3 and G-15-5-5 can solubilize tricalciumphosphate and hydroxyapatite.To study their ability of phosphate-solubilizing by means of phosphorus atomization,liquid culture and outdoor pot experiment.Specific experimental results are as follows:(1)The phosphorus index of Q-13-3-3 on NBRIP medium containing tricalcium phosphate and hydroxyapatite was 2.597 and 2.087,respectively.The phosphorus index of G-15-5-5 on NBRIP medium containing tricalcium phosphate and hydroxyapatite was 1.375 and 1.87,respectively.(2)The solubilization amount of Q-13-3-3 in NBRIP medium containing tricalcium phosphate was 676.616?g/mL.The bacterial phosphorus content was 7.522?g/mL.The phosphate-solubilizing rate reached 67.89%and the pH dropped from 7.3 to 4.21.The number of bacteria reached 3.97×10~8CFU/mL when the cells reached the stable stage.The solubilization amount of Q-13-3-3 in NBRIP medium containing tricalcium phosphate was563.491?g/mL.Thebacterialphosphoruscontentwas7.522?g/mL.The phosphate-solubilizing rate reached 67.89%and the pH dropped from 7.3 to 4.32.The number of bacteria reached 4.58×10~8CFU/mL when the cells reached the stable stage.(3)The solubilization amount of G-15-5-5 in NBRIP medium containing tricalcium phosphate was 684.42?g/mL.The bacterial phosphorus content was 9.36?g/mL.The phosphate-solubilizing rate reached 69.42%and the pH dropped from 7.3 to 4.04.The number of bacteria reached 1.78×10~8CFU/mL when the cells reached the stable stage.The solubilization amount of G-15-5-5 in NBRIP medium containing tricalcium phosphate was617.549?g/mL.Thebacterialphosphoruscontentwas8.822?g/mL.The phosphate-solubilizing rate reached 60.20%and the pH dropped from 7.3 to 4.24.The number of bacteria reached 1.80×10~8CFU/mL when the cells reached the stable stage.(4)The pot experiment was carried out on the Q-13-3-3 with wheat as the experimental material.The results of the experiments show that compared with the treatment with only insoluble phosphate addition,the biomass treated with the addition of insoluble phosphorus and Q-13-3-3,including plant height,tiller number,root and stem fresh weight and dry weight,Were significantly improved and the difference was significant.At the same time,the uptake of phosphorus of winter wheat and the available phosphorus content in soil were also increased.Among them,the content of phosphorus of root increased by 88.78%compared with the treatment with only tricalcium phosphate.The content of phosphorus of the shoot increased by 89.39%.Compared with the treatment with hydroxyapatite,the contents of phosphorus of root were increased by 52.75%.The content of phosphorus of shoot was increased by 52.86%.This shows that Q-13-3-3 can promote the decomposition of insoluble phosphorus in the soil and the release of available phosphorus to meet the supply of plant growth.(5)By morphological,physiological and biochemical experiments and 16S rDNA molecular identification,Q-13-3-3 and G-15-5-5 were identified as Pseudomonas moraviensis spp.