The effect of salt stress on some physiological and biochemical characteristics in the wheat cultivars

Salinity is one of the most important abiotic stresses reducing wheat yield in most parts of the world. Therefore, in the present study, we investigated the response of some physiological and biochemical characteristics in two wheat cultivars namely; ‘Karkheh’ (salt sensitive) and ‘Golestan’ (salt tolerant) to salinity stress (0 and 200 mM NaCl). The results showed significant increase for activities of antioxidant enzymes such as catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX), in ‘Golestan’ under salinity. Furthermore significant increase in CAT activity was found in ‘Karkheh’ under saline situations compared the control. Salt stress elevated the amounts of malondialdehyde (MDA) in both cultivars. However, the increasing rate in ‘Karkheh’ was more than (two times) that of ‘Golestan’. Membrane stability index (MSI) was not affected by salinity in ‘Golestan’ but increased at ‘Karkheh’. Both cultivars displayed increasing trend in Na+ content and K+/Na+ ratio. However, K+/Na+ ratio of ‘Golestan’ was greater than one due to salinity. Also, this cultivar obtained significantly higher amounts for soluble sugars content under salt stress compared to control. The studied parameters elucidated that salt resistance of ‘Golestan’ might be due to increased activity of antioxidant enzymes, low lipid peroxidation, assumingly minimum change in membrane stability index and more K+/Na+ ratio along with significant increase in soluble sugars and its probable ability to isolate Na+ in vacuoles.