Effect of salt stress on ion content, proline and antioxidative enzymes of two safflower cultivars (Carthamus tinctorius L.)

Salinity is a major limiting factor in the agricultural productivity, especially in countries where irrigation is an essential aid to agriculture. Effect of salinity on proline content, antioxidative enzymes activity such as catalase and peroxidase and ion content such as Na+, K+, Ca2+ of Cyprus and Isfahan local cultivars of safflower were investigated. Salinity levels that were employed: control (without salt), 2, 4, 6 and 8 dS/m NaCl. Experiment was carried out factorially in a randomized complete block design (RCBD) with three replications and period of this study was 70 days. Growth of both cultivars decreased under salt stress. With increasing NaCl concentration up to 6 dS/m growth of Cyprus cultivar was completely inhibited. Results indicated that, in high level of salinity, proline content increased and Cyprus cultivar had greater proline content. Antioxidative enzymes activity such as catalase and peroxidase increased, Cyprus cultivar had greater peroxidase activity but in Isfahan local cultivar catalase activity was higher. By increasing salt levels Na+ content was increased, by contrast, Ca2+ and K+ content decreased significantly. Decrease in Ca2+ and K+ content of Isfahan local cultivar was higher compared to Cyprus cultivar. In both cultivars, Na+/K+ and Na+/Ca2+ ratios increased under salt stress.