تاثير تنش شوري بر ميزان فعاليت آنتي‌اكسيدان‌ها و رشد گياهچه ژنوتيپ‌هاي گلرنگ

Effects of Salt Stress on antioxidants activity and seedling traits of Safflower (Carthamus tinctorius L.) Genotypes

به منظور ارزيابي اثر تنش شوري بر فعاليت آنزيمهاي آنتي اكسيدان و رشد گياهچه ژنوتيپ­ هاي گلرنگ آزمايشي به صورت فاكتوريل در قالب طرح كاملاً تصادفي در سه تكرار انجام شد. فاكتورهاي آزمايشي شامل شش ژنوتيپ گلرنگ (اراك، اصفهان، خراسان، كوسه C111، AC-stirling و Saffire) و پنج سطح شوري شامل محلول 0 (شاهد)، 50 ، 100، 150 و 200 ميلي مولار نمك طعام بود. نتايج آزمايش نشان داد كه با افزايش شدت تنش شوري ميزان فعاليت دو آنزيم آسكوربات پراكسيداز و سوپر اكسيد‌ديسموتاز افزايش يافت اما در سطح شوري 200 ميلي­ مولار نمك، فعاليت اين آنزيم­ ها كاهش پيدا كرد. تحت تأثير تنش شوري، بيشترين فعاليت آنزيمهاي آنتياكسيدان سوپراكسيد ديسموتاز و آسكوربات پراكسيداز در ژنوتيپ اصفهان و كمترين فعاليت اين دو آنزيم در ژنوتيپ AC-Stirling مشاهده شد. برهم كنش تنش شوري و ژنوتيپ بر صفات گياهچهاي گلرنگ معنيدار نبود اما ژنوتيپهاي گلرنگ Saffire داراي بيشترين طول ساقهچه، وزن خشك ريشهچه و طول ريشهچه بر ساير ارقام برتري داشتند.

Salt stress is one of the major a biotic stresses especially in arid and semi-arid regions. This investigation was conducted to evaluate the effects of the salt stress on APX and SOD activities in safflower genotypes based in a factorial experiment as a randomized complete block design (CRD) with three replications. The experimental factors were six genotypes of safflower (Arak, Isfahan, Khorasan, C111, AC-stirling and Saffire) and five levels salt stress (0(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 over other genotypes. Maximum activity of SOD was 99.16 uni/g Fw for Isfahan genotype under 150 Mm NaCl. In general, it seems that Isfahan genotype had more tolerance to salinity and AC-stirling was sensitive to salt stress. The results showed that Isfahan genotype had the greatest APX activity with 91unit/gFW while AC-stirling has the lowest content with 58unit/g FW at control treatment. The activity of both enzymes increased with salt stress, that this increase was dependent on genotype. APX and SOD activity decreased at the 200 Mm NaCl concentrations. The reason for declining in enzyme activity may be returned to enzyme protein damage by high salt stress or adaptation of plants to salt stress. Analysis of seedling traits showed that similar to antioxidants context, the genotypes of Isfahan and Ac-sterling had the most and the least values for all of the studied traits. The result showed that Isfahan genotype could be proposed for salt breeding programs in safflower.