Study of the Effect of Elicitors Application on Osmotic Regulation, Cell Membrane Stability, ‎Photosynthetic Pigments and Essential Oil Yield in Hyssop under Drought Stress

In order to investigate the effect of chitosan and salicylic acid elicitors on osmotic adjustment and some physiological traits of Hyssop under experimental drought conditions, an experiment has been carried out as a split plot design with randomized complete block design with three replications at research farm of Gonbad Kavous University during 2018-2019. Irrigation factor at three levels include 7, 14, and 21 days irrigation interval as main factor and four levels of spraying including no elicitor (control treatment, spraying), salicylic acid (300 mg. l-1), Chitosan spraying (5 g. l-1), and combination of salicylic acid and chitosan, considered as auxiliary agents. Results of analysis of variance show that the interaction between spraying and irrigation has had significant effects on ion leakage, chlorophyll a content, soluble sugar, and malondialdehyde content but insignificant impacts on carotenoid and essential oil yield. Spraying of salicylic acid, with 17% reduction in ion leakage and 40% reduction in plant malondialdehyde, compared to the control, increase the stability of cell membranes under 21-day irrigation stress. In the same treatment, chitosan has increased the amount of photosynthetic pigments and total chlorophyll by 51%, compared to the control. According to the results, salicylic acid and Chitosan have been able to increase the ability of hyssop in response to water deficit stress by activating different tolerance mechanisms.