Evaluation of salinity tolerance in two safflower cultivars using ions relations and biochemical traits

To investigate salinity tolerance in two safflower cultivars and identify the most important traits affecting salinity tolerance in safflower cultivars (Carthamus tinctorius L.), a greenhouse experiment was conducted as factorial arrangement based on completely randomized design with four replications. Treatments were irrigation water salinity (2, 4, 8 and 12 dS/m) and safflower cultivars (Sofeh and Zendehrud). Plant dry weight in Sofeh cultivar decreased 13, 30 and 58% respectively, while, plant dry weight of Zendehrud cultivar reduced 9, 28 and 40% under salinity levels. The higher concentration of chlorophyll a, b, SPAD, peroxidase and superoxide dismutase activity was found in Zendehrud cultivar under all salinity levels. Enhancement of Na concentration in shoot and root, proline and malondialdehyde was greater in Sofeh cultivar compared to Zendehrud cultivar. Linear regression analysis revealed significant and negative relationships between plant dry weight with Na concentration in leaf and root and proline content. Plant dry weight was significantly and positively associated with Kﳖ ratio, peroxidase, superoxide dismutase and chlorophyll a. In general, it was concluded that Na concentration in root, shoot (stem leaf), peroxidase and superoxide dismutase activity can be used as reliable indicators in identifying salinity tolerant cultivars of safflower