Studies On Screening And Solubilizing Effects Of Phosphorus Solubilizing Bacteria In Red Soil

Phosphorus solubilizing bacteria in soil plays an important role in phosphorus cycling and converting insoluble phosphate into soluble forms. Screening and comparing of Phosphorus solubilizing bacteria were carried out from red soil of different utilization patterns in Jiangxi province, and 7 isolates of high performance phosphorus solubilizing bacteria were obtained. The isolate CY06 was studied on its basical incubation conditions, phosphorus solubilizing activity and mechanism. Isolate CY06 was inoculated in red soil of different treatments to studyit's phosphorus solubilizing effects and the effecting factors.The results are as follows:Phosphorus solubilizing bacteria were screened from red soil of different utilization patterns,such as Tea, Soybean, Peanut and Citrus plantation. 15 isolates were isolated and their profile of colony shape, growing speed and phosphorus solubilizing activities were evaluated through solid and broth culture. Results showed that 7 isolates had been selected and their HD/CD values ranged from 1.47 to 3.45, and c in broth culture were between 26.49 and 136.27 mg·L^-1. The isolate CY06 showed higher phosphorus solubilization compared to other isolates and it seems to be more efficient in solubilization of AlPO₄ than other insoluble phosphates. It showed great potential as superior isolate for high efficiency biological phosphorus fertilizer.In orthogonal experiment(L₉3⁴), we discovered that each combination included varies sources of C, sources of N, pH and incubation time had great influence on the growth of isolate CY06. Results showed that various N sources were the major effecting factor while C sources were minor factor followed by pH, and the lowest effecting factor was incubation time. Influence of different physical and chemical factors on the growth of isolate CY06 were investigated through liquid incubation experiment. The results showed that the isolate CY06 could live in slightly alkaline conditions with the pH ranged from 4.5 to 11.0 and the optimal pH was 8.5⁹.0; PSB was able to thrive and grow well when its volume was 20ml in a 100ml flask, which was considered as optimal volume; the temperature for the largest number of cell after 3 days' incubation was 30℃. Sucrose was the best source of carbon while the solubilized phosphorus content of isolate CY06 was 18.68 mg·L^-1 and it was significantly higher than other C sources. The most suitable N source was NH₄⁺ for the isolate CY06. The results showed that Na⁺, Mg²⁺, K⁺ and Fe²⁺ could improve the the solubilized phosphorus content by isolate...