Physiological and nutritional responses of chickpea (Cicer arietinum L) to salinity

The aim of this study was to evaluate growth, nodulation, nitrogen fixation, and ionic repartition in 2 chickpea varieties, namely Chetoui and Amdoun, which are grown under salt stress. Inoculated seedlings were grown in a nutrient solution that lacked NaCl (control) or supplemented with 25 or 50 mM NaCl. Whole plant and nodule growth, nitrogen fixation and sodium, and chloride and potassium partitioning were subsequently evaluated. In comparison to Chetoui, Amdoun maintained a high level of whole plant and nodule growth and had a greater nitrogen fixation activity. Nitrogenase activity measurements demonstrated that nodule senescence was more precocious in Chetoui than in Amdoun. Genotypic differences were observed at the level of Na+, Cl-, and K+ distribution between organs: Amdoun showed the lowest leaf and nodule Na+ and Cl- concentrations and the highest K+ concentrations in these organs, particularly under severe salinity (50 mM) condition. These findings suggest that the relative tolerance of Amdoun is linked to its ability to protect its photosynthetic and symbiotic apparatus against the toxic Na+ and Cl- ions and to ensure an appropriate K+ supply of these organs.