Screening and characterization of rhizospheric phosphate solubilizing bacteria and their growth promoting effect on Mung bean (Vigna radiata)

Abstract

Soil microorganisms are supportive in the transformation of soil phosphorus (P) and are thus an important component of the soil P cycle. Through their solubilizing and mineralizing abilities phosphate solubilizing microorganisms are effective in releasing P both from inorganic and organic pools of total soil P. To exploit this potential, the phosphate solubilizing bacteria were isolated from the rhizospheric soil. The six isolates were obtained in preliminary study. Out of six isolates two promising isolates [PSB-3 and PSB-6] were selected for study of metabolic diversity. The phosphate solubilization potential of PSB 3 was 17.34mg/l and PSB 6 was 19.68 mg/l. The plant growth promoting effect of PSB-3 and PSB-6 was assessed in pot study on Mungbean (Vigna radiata) by seed application, soil application and combination of seed and soil application in presence of 40 kg P2O5/ha. The parameters studied were germination time, number of leaves, shoot length and root length. The inoculation of isolates resulted in reduction in germination time, increase in number of leaves, increase in root length and shoot length. The isolate PSB 6 gave superior results as compared to isolate PSB 3. The combination of two isolates also gave beneficial effects. The study demonstrated that the use of selected isolates having multifaceted beneficial traits would be highly effective for improving growth and yield of crops.