Abscisic acid modulation of drought tolerance and essential oil biosynthesis in Lavandula Coronopifolia Poir

Global warming, climate change, and drought are global issues. Thus, drought-tolerant and water-efficient plant species must be chosen. Selection helps maintain crop productivity. Arid-area xerophytic plant Lavandula coronopifolia Poir has little scientific research on its water use and drought tolerance. This study examined the biochemical and phytochemical changes in this plant after ABA treatment and drought stress. Specifically, we analyzed key physiological parameters (relative water content and biomass), biochemical markers (proline content, superoxide dismutase and catalase enzyme activities), and phytochemical components (essential oil composition including monoterpenes and sesquiterpenes). The drought stress treatments were applied at 50-60% and 30-40% of field capacity, while ABA was applied at concentrations of 15 and 30 µM. In low-water conditions, plant biomass and dry weight decreased. However, external ABA application increased RWC, proline, antioxidant response, essential oil percentage, and yield. It reduced drought's negative effects. Additionally, principal component analysis (PCA) found that measured variables explained 88.42% of trait variance. Changes in essential oil composition, including increased oxygenated monoterpenes and sesquiterpene hydrocarbons, were considerable. Significant changes were noticed in linalool (30.76%), decanal (20.90%), linalyl acetate (21.39%), Kessane (11.50%), and Hexadecane (15.91%). These results are indicative of the excellent drought tolerance of L. coronopifolia and ABA-mediated adaptive strategies, and may provide a basis for future applications in agriculture and essential oil production under water-stress conditions.