Effect of pesticides on phosphate solubilization by Aspergillus spp. isolated from Rhizosphere

摘要

The impact of three pesticides, endosulfan, mancozeb and neem oil at concentrations of 10, 25 and 50 mu g/mL on phosphate solubilization by Aspergillus spp., isolated from the rhizosphere of groundnut and foxtail millet, was investigated. The phosphate released from the insoluble tricalcium phosphate supplemented to the modified Pikovskaya's medium was significantly less in cultures of Aspergillus spp. treated with three concentrations of the pesticides when compared with untreated controls. The inhibitory effect of the pesticide lasted up to 12 days of incubation. Attempts to isolate acid phosphatase to homogeneity were not successful. However, the relative molecular mass of the enriched protein was found to be 62 kDa. The present observation clearly suggests that the regular agriculture practices such as the use of pesticides even at the recommended doses would greatly affect microbial solubilization of inorganic phosphates like superphosphate.