Exploring the Interaction Effect of Methyl Jasmonate and Salinity on Germination and Activity of Antioxidant Enzymes of Garden Cress (Lepidium sativum L.)

Salinity is one of the most important environmental factors that limits the growth and production of plants around the world. The identification and use of compounds that can increase the tolerance of plants against environmental stresses such as salinity are important from a theoretical and practical perspective. Methyl jasmonate is one of the known plant hormones that reduces the harmful effects of stress. In this study, the effect of seed pretreatment with methyl jasmonate for six days at three concentrations (0, 5, & 10 μM ) on the enhancement of salt tolerance at three levels (0, 50, & 100 mM NaCl) of Garden cress seedlings was examined. Salt stress reduced the germination and growth of cress while the amount of hydrogen peroxide, lipid peroxidation, and the activities of APX and GPX dramatically increased. Pretreatment of Garden cress seedlings with methyl jasmonate had no significant effect on the activity of GPX, while it obviously reduced the content of hydrogen peroxide and malondialdehyde, and significantly increased the root growth and the activity of APX. By activating enzymatic antioxidant defensive system, the use of methyl jasmonate increases the resistance of plants to oxidative stress caused by salinity and drought. Since these enzymes play an important role in protecting cells, especially photosynthetic apparatus, by removing oxygen free radicals, the positive effects of methyl jasmonate pretreatment performance in increasing maintenance of the membrane correlation and improvement growth is reflected in this study.