Pseudomonads fluorescent is one of the most important plant growth promoting bacteria that increase plant yield and growth through several different mechanisms.
They have been reported many times for their ability to dissolve the zinc insoluble compounds. In this research, 40 isolates were evaluated for their ability in solubilization of ZnO, ZnS, and ZnCO3 compounds. The results indicated that 20 percent of the examined isolates could dissolve ZnO and ZnCO3 salts, but none of them could dissolve ZnS. Zinc solubilizing isolates were investigated for their growth stimulating factors. The results demonstrated that all of the zinc solubilizing isolates could produce auxin and siderophore and they also could dissolve phosphate insoluble compounds in both solid and liquid media. ACC-deaminase was not produced in all of the isolates, except P1. None of the strains could produce HCN except for GRP3. The effect of the selected strains on zinc uptake was determined in greenhouse condition. P19 was selected as the most effective strain. It could increase zinc concentration up to 50.1 mg.kg-1 in shoot, at 500 mg.kg-1 concentration of ZnCO3.