Effect of Salt Concentration and pH on Soil Inhabiting Fungus Penicillium citrinum Thom. for Solubilization of Tricalcium Phosphate

Abstract

Aim of this studies, to improve phosphate solubilization activity of Penicillium citrinum at different salinity condition, carbon sources and varying level of pH. Plant Growth Promoting Fungus (PGPF) isolated from rhizosphere of sugarcane and identified as Penicillium citrinum Thorn. was tested for its phosphate solubilizing ability on four carbon sources viz., glucose, sucrose, glycerol and mannitol, sources of salinity viz., NaCl, CaC12 and KCl at varying range of reaction (pH) in vitro condition. Among the carbon sources, Penicillium citrinum Thorn. was found to be maximum significant solubilization of tricalcium phosphate (461 pg mL ,) in presence of glucose as carbon source, while minimum phosphate solubilization (421 pg mL ,)in presence of sucrose. Further, the effect of different salinity (NaCl, CaC12 and KCl) was tested at different pH (6.0, 7.0 and 8.0) under in vitro condition. Presence of 1% CaC12 at pH 8 in broth culture was maximum solubilization of tricalcium phosphate (455 pg mL ,) than other salt concentration (NaCl and KCl) by this fungal strain of P. citrinum Thorn. Results of this studies was found suitable carbon source as glucose for more solubilization of tricalcium phosphate. Also salinity effect on solubilization oftricalcium phosphate by P. citrinum was showed maximum significant in 1% CaC12 at pH 8.0. This finding can provide great benefit in the maintaining the available phosphates for crops in saline and alkaline soils. A large fraction of land arid and semiarid regions is affected by salinity in India. About 7.5 million of hectares of land are saline or alkaline, which is improved by Penicillium citrinum.