Journal of Plant Process and Function

.Salt stress is one of the major abiotic stresses especially in arid and semi-arid regions. This investigation was conducted to evaluate the effects of the salt stress on Ascorbate Peroxidase (APX) and Superoxide Dismutase (SOD) activities in safflower genotypes based in on a factorial experiment as a Completely Randomized Design (CRD) with three replications. The experimental factors were six genotypes of safflower (Arak, Isfahan, Khorasan, C111, AC-stirling and Saffire) and five levels of salinity (zero as control, 50, 100, 150 and 200Mm NaCl). There was a significant difference between genotypes in activity of SOD and APX enzymes under salt stress, with notable superiority of Isfahan genotype than other genotypes. Maximum activity of SOD was 99.16 uni/g Fw for Isfahan genotype in 150 Mm NaCl. In general, it seems that Isfahan genotype was more tolerant to salinity though, AC-stirling was the most sensitive genotype to salt stress. The results showed that Isfahan genotype had the greatest APX activity with 91unit/g FW although, AC-stirling had the lowest content with 58unit/g FW at control treatment. The activity of both enzymes increased with increasing salinity levels, which depended upon genotypes. APX and SOD activity decreased at 200 Mm NaCl concentration. APX and SOD activity decreased at the 200 Mm NaCl concentrations. Analysis of seedling traits showed that, the genotypes of Isfahan and Ac-sterling had the most and the least amounts of measured traits, respectively. In general, Isfahan genotype of safflower could be recommended in salt breeding programs.