Jasmonic acid-induced metabolic responses in bitter melon (Momordica charantia) seedlings under salt stress

In the present study, effects of foliar application of 150 mu M Jasmonic acid (JA), an endogenous plant growth regulator, on alleviation oxidative stress resulted from without (0 mM), low (50 mM), moderate (150 mM), and high (300 mM) NaCl in bitter melon (Momordica charantia) seedlings was investigated. High salt stress significantly decreased growth components including root length, leaf morphological properties, leaf water content, plant biomass and levels of pigments, soluble sugars, starch and proteins, but accumulated higher amounts of proline, free amino acids and the activities of ascorbate peroxidase (APX), catalase (CAT), polyphenol oxidase (PPO) and pyrogallol peroxidase (PPX). Exogenous JA treatment alone or combined with salt stress improved growth components with hyperaccumulation of soluble sugars, proteins, amino acids, proline and PPO activity, but was associated with a decrease in the activity of H2O2-decomposing enzymes. These results suggest that exogenous JA treatment can effectively raise salt stress tolerance of bitter melon seedlings through modifying allocation of carbon and nitrogen metabolism to adjust levels of metabolites and directing them to the growth processes.