Improving Effects of Salicylic Acid and Jasmonic Acid on Alleviation of Water-Deficit Stress on Thyme (Thymus vulgaris L.) Growth, Physiology, and Essential oil

Karimi, Zahra; Nasri, Mohammad; Oveysi, Meysam; Kasraei, Pourang; Larijani, Hamid Reza

doi:10.22059/ijhst.2024.371663.761

Improving Effects of Salicylic Acid and Jasmonic Acid on Alleviation of Water-Deficit Stress on Thyme (Thymus vulgaris L.) Growth, Physiology, and Essential oil

Document Type : Research paper

Authors

Department of Agronomy, Faculty of Agricultural, Islamic Azad, Varamin-Pishva Branch, Tehran, Iran

10.22059/ijhst.2024.371663.761

Abstract

Iran encompasses various climate zones, with approximately 85% of its agricultural land located in arid and semi-arid regions. To mitigate the effects of drought stress and enhance crop adaptation and yield, numerous advanced techniques, including hormone applications, have been extensively studied. This research aimed to investigate the effects of foliar application of different concentrations of salicylic acid and jasmonic acid on the morphological, physiological, and biochemical characteristics of garden thyme under water deficit stress conditions. The study was conducted using a split factorial design within a randomized complete block framework, with three replications at the Varamin and Absard research fields in Iran during the 2019 growing season. The primary factor was irrigation, assessed at two levels: normal and water-deficit stress. Sub-factors were the foliar application of salicylic acid and jasmonic acid at various concentrations, and the treatment groups were in factorial arrangements. Salicylic acid was applied at concentrations of 0, 25, and 50 mg L-1, while jasmonic acid was applied at 0, 1, and 2 mg L-1. The results demonstrated that water deficit stress significantly reduced plant height, dry weight yield, and chlorophyll a, b, and total chlorophyll content, while it increased proline accumulation. Under water deficit stress, the maximum levels of dityrosine and 8-hydroxy-2' deoxyguanosine (34.18 and 13.52 nmol mg-1 protein, respectively) were observed, which were 11% and 20% higher, respectively, than those under well-watered conditions. Furthermore, the interaction between foliar applications of different concentrations of salicylic acid and jasmonic acid mitigated the detrimental effects of water deficit stress, enhancing the tolerance of garden thyme. Overall, the findings suggest that under drought conditions, the application of salicylic acid and jasmonic acid can significantly improve the performance of garden thyme.

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