Physiological and Biochemical Responses of Acacia Seyal (Del.) Seedlings under Salt Stress Conditions

In this study, the first experiment analyzed the effects of 0, 85, 171, 256, and 342 mM sodium chloride (NaCl) on the germination of Acacia seyal seeds. In the second in vitro experiment, the effects of inoculation with two rhizobial strains on growth, physiological, and biochemical responses of A. seyal seedlings was evaluated at four levels (0, 85, 171, and 256 mM) of NaCl. Results showed that at 342 mM NaCl, germination rate of A. seyal seeds declined by 56% from the control value, while any germination was recorded for Acacia bivenosa and Acacia sclerosperma seeds at the same salt level. Salt stress gradually decreased the growth, the soluble protein and the leaf-chlorophyll contents of A. seyal seedlings. However, rhizobial inoculation limits these adverse effects of salt on physiological and metabolic processes responses. A. seyal exhibited a moderate halophytic behavior; nodulation was enhanced by moderate salt stress.