The effect of salinity on some physiological and biochemical characteristics of alfalfa

To evaluate the effects of different concentrations of salinity (control and 12 dS m-1) on morphological and physiological aspects of 10 alfalfa cultivars, an experiment was conducted using a randomized complete block design with factorial treatments in three replications.The results showed that salinity stress significantly reduced dry matter, Kﳖ ratio and shoot and root K concentrations. The sodium concentration of the plants increased with salinity stress, and the salt tolerant cultivars showed lesser sodium transfer into their tissues resulting in a higher shoot and root Kﳖ ratio compared to susceptible cultivars. K concentration in shoot as well as shoot Kﳖ ratio had significant positive correlations with shoot dry matter of 0.762**and 0.835** respectively. On the other hand there was a significant negative correlation between shoot dry matter and shoot Na concentration (-0.831)., showed the highest significant correlation with shoot dry matter. Therefore, it seems that among the traits studied, the Na concentration in the shoot may be considered as an appropriate indicator for selection of salt tolerant alfalfa cultivars. The observed negative correlation between sodium concentration and the chlorophyll content (-0.551) indicate that the plant metabolism has been adversely affected by salinity stress.