Changes in growth, essential oil composition and biochemical traits of peppermint in response to coapplication of zinc and methyl jasmonate in soilless culture

Zinc (Zn), a micronutrient, is a source of energy for essential oil (EO) biosynthesis. Methyl jasmonate (MeJA) is a plant growth regulator that has favorable effects on EO quality and quantity. The main objective of this study was to evaluate the interaction effect of Zn and MeJA on the phytochemical traits and EO compositions of peppermint cultivated under soilless conditions. Zn omission and the highest Zn concentration (0.1 mgL-1), which are stress conditions for plants, increased phytochemical traits as well as EO content, and 1 mM MeJA was more suitable for increasing these parameters. The major classes of peppermint EO components were oxygenated monoterpenes, sesquiterpene hydrocarbons, and monoterpene hydrocarbons. The major constituents included menthol, menthone, menthofuran, and 1,8-cineole. Elicitation of peppermint with MeJA at different Zn levels modified the EO composition. The highest menthol content (50.1%) was observed in the 1 mM MeJA and 0.025 mgL-1 Zn treatment groups. In conclusion, this study indicated that Zn and MeJA could be appropriate compounds for changing phytochemical compounds, antioxidant activity, and EO composition.