Document Type : Original Article

Author

• Farhad Azarmi-Atajan

Associate Professor, Soil Science and Engineering Department, Agricultural College, University of Birjand, Birjand, Iran.

Abstract

Environmental stresses such as soil salinity and drought as well as poor soil fertility play an important role in reducing agricultural production. The aim of this study was to evaluate the tolerance of bacteria isolated from the rhizosphere of saffron, pistachio and barberry plants to salinity and drought stresses, as well as their ability to solubilize phosphorus and produce indole acetic acid in laboratory conditions. thus, 10 bacterial isolates were isolated from the rhizosphere of each plant and evaluated for growth in culture media with different salinity levels (0, 10, 20, and 40 dS/m) and drought (0, -5, and -10 bar), and solubilization of tri-calcium phosphate, and indole acetic acid production. The results showed that with increasing salinity and polyethylene glycol concentration in the culture medium, bacterial growth decreased. Bacteria isolated from the rhizosphere of barberry plants showed greater ability than other isolates to grow in high salinity and drought levels. The highest amount of phosphorus released in the liquid medium was 629 μg/mL, which belonged to isolate S4. The solubility of phosphorus by the isolates varied in the range of 237-629 μg/ml. The average solubility of tricalcium phosphate in bacteria isolated from the rhizosphere of saffron, pistachio and barberry plants was 484, 472 and 393 μg/ml, respectively. The production of indole acetic acid by the isolates varied in the range of 18.83-3.23 μg/ml. Therefore, these isolates can be used for testing them to prepare microbial inoculants to induce plant resistance and provide nutrients under stress conditions.

Keywords

• Indole acetic acid
• Tri-calcium phosphate
• Environmental stresses
• Plant growth-promoting microorganisms
• Sodium chloride

Main Subjects

• Drought