Effects of methyl jasmonate on growth, antioxidants, and carbon and nitrogen metabolism of Glycyrrhiza uralensis under salt stress

We investigated the effects of 0.025 or 0.05 mM methyl jasmonate (MeJA) on the growth characteristics, antioxidant enzyme activities, non-enzymatic antioxidant content, and carbon and nitrogen metabolizing enzyme activities in Glycyrrhiza uralensis exposed to 100 mM NaCl. Results showed that salt stress decreased the stem length and lateral root number and the treatment with 0.025 or 0.05 mM MeJA increased the root length of salt-stressed G. uralensis seedlings but decreased root diameter, stem length, and stem diameter. MeJA application modulated oxidative stress in salt-stressed G. uralensis seedlings. It decreased the catalase activity but enhanced peroxidase activity and ascorbate content. However, treatment with 0.05 mM MeJA significantly increased the malondialdehyde content of salt-stressed seedlings. Salt stress inhibited carbon and nitrogen metabolism. The application of MeJA enhanced the activities of sucrose synthase, and sucrose phosphate synthase, and nitrate reductase in salt-stressed seedlings.