ISOLATION AND EVALUATION OF HALOTOLERANT RHIZOBACTERIA FROM XANTHIUM STRUMARIUM L. AS PLANT GROWTH PROMOTING RHIZOBACTERIA

Rhizosphere inhabiting bacteria are indirectly or directly modulate plant growth and physiological attributes by secretion of unique metabolites. This study was conducted to isolate and characterize rhizobacteria from a halophytic plant Xanthium strumarium L. to evaluate for their ability to promote growth of maize plant (Zea mays L.). For this purpose four different rhizobacteria were isolated from X strumarium growing in Mardan district. All isolates were characterized for the production of phytohormones (Indole acetic acid (IAA) and Cytokinins), nitrogen fixation, phosphate solubilization and salt tolerance ability. All the isolates were biochemically characterized and identified as Staphylococcus sp. (Xs1), Arthrobacter Sp. (Xs2), Enterobacter sp. (Xs3) and Pseudomonas sp. (Xs4). All isolates showed IAA and cytokinins production and one isolate showed nitrogen fixing ability but none showed phosphate solubilization. Of the isolated strains Xs1 and Xs2 showed growth in LB agar containing up to 5.5% NaCl concentration. Seed germination experiments revealed increase in root and shoot lengths, fresh and dry weights of maize seedlings in treated seedlings as compared to control. In pot experiment, growth parameters such as root length, shoot length, fresh and dry weight after 15 days of growth showed enhancement as compared to control. Staphylococcus sp. (Xs1) was found most effective to increase growth of maize seedlings.