Application of Chelate and Nano-Chelate Zinc Micronutrient Onmorpho-physiological Traits and Essential Oil Compounds of Peppermint (Mentha piperita L.)

Peppermint (mentha piperita l.) from lamiaceae family is one of the most important medicinal plants, used in food, sanitary and cosmetic industries. the aim of this study was to examine the effects of nano zinc and zinc-chelate on morpho-physiological traits and essential oil composition of peppermint. a factorial experiment was conducted based on randomized complete block design (rcbd) with three replications in karaj, iran, in 2016. treatments were zinc micronutrient in two levels (zinc-chelate and zinc nanoparticles) and concentration in four levels (0, 0.5, 1 and 1.5 g/l). the zinc micronutrient was applied in foliar spraying in three times of the interval of 15 days up to flowering stages. results showed that both of nano zinc and zinc-chelate micronutrient significantly increased all of morpho-physiological traits than that for control. the higher values were obtained in zinc-chelate (1.5 g/l) and nano zinc (1 g/l), respectively. the effects of treatments were significant at 21 out of 34 compounds. the higher compounds with average values of 19.7%, 7.8%, 5.9%, 5.7%, 4.9% and 4.1% were obtained in menthol, menthone, menthofuran, piperitone, menthyl acetate and beta-caryophyllen, respectively. nano zinc (1.5 g/l) had increased menthol, menthone and menthofuran content up to 28%, 61% and 237% higher than the control, respectively. t. it was concluded that foliar spraying of nano zinc (1 g/l) in flowering stage had increased dry matter yield and essential oil content and spraying of nano zinc (1.5 g/l) had increased essential oil composition of peppermint.