Changes in Germination, Antioxidant Enzyme Activities and Biochemical Contents of Safflower (Carthamus tinctorius L.) Under Different Salinity Levels

The present study was carried out using Dinçer and Olas safflower varieties at 5 different salt (NaCl) concentrations (0, 50, 100, 150, and 200 mM) for 14 days. The germination percentages of the cultivars under salt conditions as well as the activities of antioxidant enzymes (SOD, CAT, POD and APX) and biochemical changes (protein and MDA) in the seedlings were determined. The germination percentage decreased with increased salt concentrations, and the greatest decrease in germination percentage was observed at a 200 mM salt concentration by 34% in both cultivars. The activity of superoxide dismutase (SOD) increased at low salt concentrations, but decreased after 100 and 150 mM salt concentrations, respectively. Catalase (CAT) and ascorbate peroxidase (APX) activities, as well as malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents, increased with increasing salt concentrations at Dinçer and Olas, but total soluble protein content decreased with increasing salt concentration. Peroxidase (POD) activity was not significantly affected by salt stress in safflower. Germination percentage showed negative correlations with CAT, MDA and H2O2 levels, and showed a positive correlation with soluble protein content under salt stress in safflower. The present results may be useful to identify mechanisms of salt tolerance involving antioxidant enzyme activities and biochemical changes in safflower seedlings.