Investiganting the effect of methyl jasmonate and titanium dioxide nanoparticles on physiological and phytochemical variations of Rosa damascena. Mill. esential oil

Rosa damascena Mill. belongs to Rosaceae family and is considered as one of the most important medicinal and industrial plant. In the present study, the effects of foliar application of methyl jasmonate and titanium dioxide nanoparticles were investigated on physiological and phytochemical traits of Rosa damascena Mill. in two separate experiments based on a randomized complete block design with 3 replications in Farsan during two growing seasons (2019 and 2020). Foliar application of methyl jasmonate (0, 0.5, 1, and 2 mM) and titanium dioxide nanoparticles (0, 100, 200, and 300 mg L-1) was performed three times with 4-day intervals before the flowering stage. Essential oil extraction was done by steam distillation (a clevenger apparatus), phytochemical evaluation was performed using spectrophotometric method, and antioxidant performance was evaluated through DPPH test. Results showed that foliar application of elicitors increased dry weight of leaves and photosynthetic pigments. The phenolic compounds of leaves and petals of R. damascena Mill. also increased in response to applied elicitors and the highest increment was observed in plants treated with 1 mM methyl jasmonate and 100 mg L-1 titanium dioxide nanoparticles. Also the results showed the positive effect of applied treatments on increasing macro (N, P, K and Mg) and micro elements (Fe, Mn, and Zn) in leaves of damask rose. Methyl jasmonate (0.5-1 mM) increased the essential oil content of the treated plants by 34.32%. According to the obtained results, methyl jasmonate applied at concentration of 1 mM is suggested to improve the physiological and phytochemical characteristics of the R. damascena plants.