Co-treatment effect of triadimefon and salt stress on antioxidant responses, NHX1 and LEA expression in two alfalfa cultivars (Medicago sativa L.) under in vitro culture

Abstract

This study was carried out to investigate the possibility of using Triadimefon as a plant growth regulator and salt stress protectant in order to decrease the adverse effects of salt stress. Two Medicago cultivars including Hamedani and Yazdi were treated with 0, 2 mg/L triadimefon (TRD) and 0, 100, and 140 mM NaCl. Salt stress increased Na+, ascorbic acid (AA), reduced glutathione (GSH), reactive oxygen species and phenol contents and activity of ascorbate peroxidase (APX), and glutathione reductase (GR), whereas decreased the K+ content and the activity of polyphenol oxidase (PPO) in both cultivars. When plants were treated with TRD and NaCl, they accumulated less Na+, K+, and ROS. Co-treatment of NaCl and TRD in both cultivars increased AA, GSH, and phenol contents, and the activities of APX and GR, whereas reduced PPO activity. Our results also showed that LEA gene was up-regulated by salt stress. TRD treatment resulted in down-regulation of this gene. Sodium/hydrogen exchanger gene was not affected by either salt or TRD treatments.