Methyl jasmonate improves metabolism and growth of NaCl-stressed Glycyrrhiza uralensis seedlings

Abstract Background and Aims Salinity is one of the major factors that affect growth and metabolism in plants. However, limited information is available on the influence of methyl jasmonate (MeJA) on antioxidant defense, carbon (C) and nitrogen (N) metabolisms in Glycyrrhiza uralensis Fisch. (G. uralensis) under salt stress. Here, this experiment was conducted to investigated the responses of antioxidant defense, C and N metabolisms of salt-stressed G. uralensis to MeJA at different concentrations. Methods G.uralensis plant seeds were grown under six conditions: control, 200 mM NaCl, and 200 mM NaCl combined with 15, 30, 45 and 60 μM MeJA. Key Results Results showed that salt stress inhibited G. uralensis growth and this adverse effect was reversed by MeJA at different concentrations. MeJA also affected antioxidant system and C and N metabolisms. In general, MeJA from 45 to 60 μM significantly enhanced superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione peroxidase (GPX) activities in salt-stressed G. uralensis seedlings, MeJA from 15 to 30 μM increased peroxidases (POD) and catalase (CAT) activities, and ascorbate peroxidase (AsA) and glutathione (GSH) contents. Thus, these changes caused a decrease in hydrogen peroxide (H2O2), superoxide radical (O2−) and malondialdehyde (MDA) contents correspondingly. Moreover, 60 μM MeJA enhanced sucrose synthase (SS), sucrose phosphate synthase (SPS) and nitrate reductase (NR) activities in salt-stressed G. uralensis seedlings. Conclusions MeJA promoted growth of salt-stressed G. uralensis seedlings by alleviating oxidative stress and strengthening C and N metabolism, these effect depended on the applied concentrations of MeJA.