Responses of alfalfa to potassium, calcium, and nitrogen under stress induced by sodium chloride

The physiological responses of alfalfa (Medicago sativa L. cv. Gilboa) to salinity (100 mM NaCl) and some inorganic nutrients (K+, Ca2+ and N as NO3-) were investigated. Salinity caused a substantial reduction in biomass, carbon assimilation rate, stomatal conductance, water use efficiency, leaf area, relative growth rate, NO3- content and nitrate reductase activity, whereas, transpiration rate was slightly affected. Inclusion of K+, Ca2+ and N as NO3- in plant nutrient medium in combination or alone brought about a marked stimulation in control plants and moderated the salinity caused reductions in NaCl treated plants. In addition, plants also exhibited differences in these parameters at two growth stages.