Mitigation of Salt Stress Toxicity in Narcissus tazetta L. by Foliar Application of Methyl Jasmonate

In the present study, the effect of foliar application of methyl jasmonate (MeJA) (0, 50, 100, and 200 µM) and salt stress (2 (non-stress), 4 and 8 dS m-1) on the improvement of salinity stress tolerance in narcissus was studied in the Research Greenhouse, Islamic Azad University of Isfahan (Khorasgan) during 2019-2020. In this research, a pot experiment was conducted, as factorial based on randomized complete block design with three replications. With increase in salinity, chlorophyll content, membrane stability index, leaf area, fresh and dry weight of shoots and roots and K concentration of narcissus decreased but Na and Cl concentrations increased in the leaves and bulbs. However, foliar-applied MeJA led to decreases in the concentration of Na and Cl and increase in the concentration of K in the plant tissue, resulting in improvement of the growth and plant biomass of the salt-stressed plants. Application of 50, 100 and 200 μM MeJA led to 5%, 14%, 7% reductions in leaf Na, 4%, 17%, 3% reductions in bulb Na, and 11%, 13%, 7% reductions in leaf Cl concentrations, respectively, of narcissus subjected to 8 dS m-1 salinity, compared to the absence of MeJA treatment. Moreover, application of 100 μM MeJA increased leaf K by 12%. Therefore, application of 100 μM MeJA was proven to be superior to other levels used in this study in increasing the tolerance of narcissus to saline conditions.