Biochemical and Physiological Changes in Response to Salinity in Leaves and Roots of Two Durum Wheat (Triticum Durum Desf.) Genotypes

Salt stress is a major abiotic stress that limits agricultural productivity in many regions of the world. To understand the molecular basis of the salt stress response, two wheat (Triticum durum Desf.) cultivars, Karim and Azizi, which are of agronomic significance in Tunisia, were grown under non-saline and saline conditions (100 mM). Leaves and roots of control and salt-stressed plants were harvested after 11 days of salt treatment. Karim cultivar may behave as a typical Na+ include, which compartmentalizes Na+ within the leaf cell vacuoles where it could be used as an osmoticum to lower the osmotic potential necessary for the maintenance of the plant hydric status. While, accumulation of K+ was greater in Karim cultivar compared to Azizi, in both organs, presenting an important manifestation of salinity tolerance. Significant changes in metabolism of antioxidative system were observed, with an increase in protein tyrosine nitration, which indicates that salinity stress induces a nitro-oxidative stress

Variations in α-, β-amylase and α-glycosidase activities in two genotypes of wheat under NaCl salinity stress

Two wheat differing in salt sensitivity, was examined for osmolyte contents and activities of α-amylase, β-amylase and α-glucosidase enzymes involved in seeds germination, in absence as well as in presence of  100, 150, 200 and 300 mM NaCl. The inhibitory effects of NaCl differed, depending on the species tested. In wild wheat specie (Triticum monococcum), with reduced germination percentage and lower relative water  content, the   increase in NaCl concentration resulted in the decrease in endogenous level of proline, total soluble sugars and activities of the main enzymes involved in the germination process. In contrast, cultivated  wheat specie (Triticum aestivum) seed in response to salt stress accumulated higher proline and total soluble  carbohydrate concentrations  which improved  their  water  status and the enzyme  activities  involved  in the germination  process. Differential response of the different species of wheat to salt stress is governed by the accumulation of osmolytes in seeds