ISOLATION OF PHOSPHATE SOLUBILIZING BACTERIA FROM RHIZOSPHERE SOIL OF ORANGE PLANTS AND THEIR ROLE IN PLANTS GROWTH PROMOTION

Plant growth promoting rhizobacteria (PGPR) mediate the soil processes such as decomposition, nutrient mobilization, mineralization, solubilization, nitrogen fixation and growth hormone production. Microorganisms having the phosphate solubilizing capacity can covert the insoluble phosphates into soluble forms through the production of organic acids. Isolation of phosphate solubilizing bacteria for the effective plant growth promotion broadens the spectrum of phosphate solubilizers available for field application. Improvement of solubilizing capacity is a important step for commercial purposes. Microbial phosphate solubilization can also improve the effectivity of mineral phosphate fertilization. There are many biofertilizers available containing phosphate solubilizing bacteria, but not all the biofertilizers can give good results in all kind of environment and in all areas. Sometimes, by using superior quality of biofertilizers there is no much gain or yield because the bacterial strain used in that biofertilizers cannot adjusted in that particular environment of soil. Like other plants rhizosphere of the orange tree is great source of phosphate solubilizing bacteria, and there is vast scope for increasing the productivity of orange tree. To increase the crop productivity and soil fertility, the phosphate solubilizing bacteria are very useful. There is no literature available on isolation of phosphate solubilizing bacteria from rhizosphere of orange tree. So, our aim is to isolate the phosphate solubilizing bacteria from the rhizosphere of the orange tree from Amravati district. During this study, the species obtained showing the maximum zone of solubilization can be further recommended for the preparation of biofertilizers which can give best results in this particular environment.