Abstract
A total of eleven phosphate solubilizing bacteria were isolated from rhizosphere soil of tomato (Solanum lycopersicum) plants. Isolates designated as PSB1, PSB2, PSB4, PSB5 and PSB7 were selected out of eleven isolates based on their clear zone diameters. They were characterized to generic level and found to belong to Pseudomonas spp. Tricalcium phosphate (TCP), rock phosphate (RP) and bone phosphate (BP) solubilizing efficiency of these isolates was studied in the laboratory at 5, 10, and 15 days of incubation. All bacterial isolates solubilized significantly (P< 0.05) higher amounts of TCP over uninoculated control. The highest P was release upon 5 days of incubation was recorded from the isolate PSB1 with 7.64 mg/50ml in the medium and the least P release was recorded by isolates PSB4 and PSB5 with a P content of 4.79 mg /50ml. At 10th day of incubation, the highest P release was recorded by isolates PSB2 (8.19 mg/50ml), PSB1 (8.10mg/ 50ml). At 15th days of incubation, the highest P release was recorded by isolate PSB7 (11.77 mg/ 50ml) and PSB2 (11.33 mg/ 50ml) and the least P released was recorded by isolate PSB5 (5.44 mg/ 50ml)). Under RP solubilization, the p released from all isolates upon 5 days of incubation was not significant as compared to the control. At 10th day of incubation, the highest P release was recorded by isolates PSB5 (5.56 mg/50ml), PSB7 (5.02 mg/ 50ml) and the least P release was observed by isolate PSB4 (3.46mg/g). At 15th days of incubation, the highest P release was recorded by isolate PSB7 (7.928 mg/ 50ml) and the least P release was recorded by isolate PSB4 (4.025mg/ 50ml). Regarding BP, the p released from all isolates except isolate PSB7 (3.020mg /50ml) upon 5 days of incubation was not significant as compared to the control. At 10th day of incubation, the highest P release was recorded by isolates PSB5 (7.37 mg/50ml), PSB7 (7.025 mg/ 50ml) and the least P released was observed by isolate PSB2 (5.47 mg/50ml). At 20th days of incubation, the highest P release was recorded by isolate PSB7 (11.09 mg/ 50ml) and the least P release was recorded by isolate PSB4 (9.06 mg/ 50ml). So, as conclusion all Psedomonas isolates were able to release P from both inorganic and organic phosphate sources.
Highlights
Phosphorus (P) is the major nutrient after nitrogen (N) that limits plant growth [1, 2]
The test phosphate solubilizing bacteria (PSB) isolates used for this experiment were PSB1, PSB2, PSB4, PSB5 and PSB7
In the present study five phosphate solubilizing bacteria designated as PSB1, PSB2 PSB4, PSB5, and PSB7 were isolated from soil samples collected from tomato growing farmer’s fields in Debrezeit district (Bishoftu)
Summary
Phosphorus (P) is the major nutrient after nitrogen (N) that limits plant growth [1, 2]. The problems of P deficiency are generally alleviated through the application of P fertilizers by field practitioners, which they use to achieve maximum plant productivity; but this practice is expensive. The repeated and injudicious applications of chemical P fertilizers, lead to the loss of soil fertility [1] by disturbing microbial diversity, and reducesyield of crops. The rest is fixed (sorbed) in the soil and use of chemical fertilizer is not sustainable in both large-scale and small-scale agriculture. Since the indiscriminate and excessive applications of chemical P fertilizers cause a profound adverse effect on the sustainability of crops and safety of the soil environment, agrarian communities are desperate to find alternative strategies that could ensure competitive yields while maintaining the nutrient pool of soils. Lamenew Fenta and Fassil Assefa: Isolation of Pseudomonas with the Ability to Solublize Phosphate from
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
