SALT EFFECTS ON SURVIVAL AND MULTIPLICATION OF CHICKPEA AND SOYBEAN RHIZOBIA

Fourteen strains of chickpea rhizobia. eight strains of soybean rhizobia and eight strains of soybean bradyrhizobia were screened for their tolerance to different concentrations of NaCl. Assessment of visible turbidity after 14 days indicated 15 strains of both chickpea and soybean rhizobia tolerant of 0.34 m NaCl. Most fast-growers were more salt-tolerant than the slow-growers. Three salt-tolerant strains were further tested for their tolerance to different salts. MgCl; was the most inhibitory salt. and soybean rhizobia were slightly more tolerant than chickpea rhizobia. Prior exposure to salt did not alter the subsequent response to the same or different salts and the same or higher concentrations. A 2% mixture of salts more representative of conditions in saline soils had no effect on survival of strains which initially multiplied in 2% NaCl but then died. © 1990.