Effect of Salt Stress on Growth and Lipid Peroxidation of Tomato (Lycopersicum esculentum) Cultivars at Vegetable Stage

This research was carried out in order to evolution effect of salt stress on physiology of two salt tolerance tomato cultivars ('Vendor' and 'Vantage') and two salt sensitive tomato cultivar ('TC-11' and 'Holia') at Islamic Azad University (Shoushtar branch), Iran, in 2010. Salt stress treatments were applied using salt solutions with EC values of 0.6 (control), 4 and 8 dS/m(-1). Salt stress induced changes in antioxidant enzymes, lipid peroxidation, leaf Na+ and K+ percentage and seedling growth. Salt treatment decreased shoots dry weight, root and shoot height, leaf RWC and leaf K+ percentage in salt sensitive cultivars ('TC-11' and 'Holia') more than salt tolerant cultivars ('Vendor' and 'Vantage'). The four cultivars showed an increase in malondialdehyde (MDA) content and Na+ percentage under salt condition, but the increase in sensitive cultivars were higher than that in salt tolerant genotypes. With increasing EC values, leaf K+ percentage was decrease in all cultivars, but this decrease was slowly in 'Vantage' cultivar. The lesser degree of membrane damage and the higher activity of CAT and GR observed in NaCl treated plants of 'Vantage' and 'Vendor' indicated that these tomato cultivars had a higher capacity for the tolerant salinity in comparison with sensitive cultivars.