Effect of Salinity on Nutrients Absorption and Symbiosis between Sinorhizobium meliloti and Different Genotypes of Alfalfa

The purpose of this experiment was to study the effect of salinity on absorption of some nutrition elements and the symbiosis of Sinorhizobium meliloti with different clones of alfalfa. Strains of Sinorhizobium meliloti were isolated from alfalfa fields in Tehran Province. After the isolation and purification processes, alfalfa seeds were inoculated with the efficient strains of symbiotic Sinorhizobium meliloti. Finally, 2 strains were selected, one of which was resistant and the other was sensitive to salinity. The effect of inoculation with these strains were investigated on the growth and the yield of 3 medicago sativa Genotypes (Hamadani, Gharayonjeh and Gharghalogh) at 3 levels of salinity (EC= 0, 6, 12 dS/m), using a completely randomized block designed in factorial form with 3 replications. Results showed that with increase in salinity, shoot and root dry weight, nodule number, and the plants concentration of nitrogen, phosphorus, and potassium decreased significantly, whereas the concentration of sodium increased. In addition, according to the results, inoculation with the Sinorhizobium meliloti strain resistant to salinity caused significant increase in shoot and root dry weight, nodule numbers, and the concentration of nitrogen, potassium, and phosphorus in comparison to the control. There were no significant differences between the alfalfa genotypes in yield or other growth indices.