Methyl Jasmonate Mitigates Drought Stress Injuries and Affects Essential Oil of Summer Savory

Drought stress reduces growth and productivity of crops in arid and semiarid regions, such as Iran. Methyl Jasmonate (MeJA) is involved in regulating plants growth and their immune responses. The main purpose of this study was to evaluate the effects of MeJA on growth and some physiological responses of summer savory (Satureja hortensis) plant under drought stress condition. Treatments consisted of three levels of drought stress including stress free conditions, mild stress and severe stress, and four concentrations of MeJA (0, 75, 150, and 225 mu M). The results showed that drought stress and MeJA application had a significant effect on morphological, physiological, and biochemical parameters. In drought conditions, some growth parameters, namely, relative water content and essential oil yield decreased and antioxidant activity, proline content, and essential oil percentage increased. The results suggest that MeJA application under drought stress can improve growth parameters as well as relative water content, proline content, antioxidant activity, and essential oil percentage and yield. The best protection appeared to be obtained from plants treated with MeJA at 75 mu M.