E. PRABHAVATI AND K.V. MALLAIAH
Abstract
Horse gram is an important pulse crop of South India. The Rhizobium strains from Horse gram were found to be highly salt tolerant. These strains were used to study the effect of NaC1 on colony growth, viability and EPS production. The percentage reduction in growth of the three isolates at 3% NaC1 over control are 49.5%, 38.6% and 56.25% respectively. At 10% NaC1 concentration and above that the colonies were hyaline and of watery consistency. The higher concentrations of NaC1 are generally antimicrobial, where only salt tolerant bacteria grow. The colonies growing at 5%, 10% & 15% NaC1 showed relatively good growth when subcultured on fresh YEMA medium without NaCI. The colonies growing at 20% NaC1 concentration yielded relatively smaller colonies. The EPS production by the three isolates generally increased with increase in NaC1 concentration from 1 to 10%. At 15% concentration it was almost double than that at 10% concentration. At 20% NaC1 concentration the EPS content was slightly decreased than that at 15%, but still higher than that at 10% concentration.