Effects of different levels of salinity and nitrogen fertilizer on some physiological and biochemical characteristics of two wheat cultivars at tillering stage

In order to assess the physiologic responses of two wheat genotypes to different levels of salinity and nitrogen (N) at tillering stage, a factorial experiment, based on completely randomized design with three replications, was performed under greenhouse conditions. Treatments were two wheat cultivars [Tajan (susceptible to salt stress) and Bam (resistant to salt stress)], five levels of salt stress ‎‎[control (1.3), 6, 8, 10 and 12 dS/m)] and two levels of N (75 and 150 kg N/ha). Results indicated that in all salinity treatments, application of 150 kg N/ha increased chlorophyll b content, total soluble proteins, SOD activity, and decreased MDA content of both ‎genotypes. Salinity decreased relative water content (RWC) of both genotypes. However, N fertilizer did not have significant effect on the mentioned parameter. In this respect, genotypic differences for salinity tolerance and fertilizer uptake caused higher levels of the N fertilizer to be more effective on Bam genotype than Tajan genotype. These results suggest that N fertilizer, as a primary nutrient for ‎physiological compounds, may alleviate the adverse effects of salinity stress on wheat at sensitive stage of tillering