Jasmonic Acid Enhances Pomegranate Resilience to Drought: Insights Into Leaf and Fruit Traits

Drought stress (DS) in arid and semi-arid ecosystems poses a significant barrier to pomegranate cultivation, profoundly affecting fruit quality and agricultural productivity. The primary objective of this study was to investigate the effects of DS at levels of 100%, 70%, 40%, and 20% field capacity (FC), and the foliar application of Jasmonic acid (JA) at concentrations of 0, 5, 25, and 50 μM, on the physiological and biochemical traits of pomegranate leaves and fruits over two consecutive years. The evaluated traits included relative water content (RWC), membrane stability index (MSI), chlorophyll index (SPAD), photochemical efficiency of photosystem II (F_V/F_M), hydrogen peroxide (H₂O₂), and superoxide dismutase activity (SOD) in leaves, as well as total phenolic compounds (TPC), total antioxidant capacity (TAC), anthocyanins, total soluble solids (TSS), and weight loss in pomegranate fruits. The results demonstrated that DS, particularly at 20% field capacity, significantly reduced RWC, MSI, SPAD, and F_V/F_M, whereas increasing H₂O₂ and SOD levels. Jasmonic acid application effectively mitigated these adverse effects, with higher concentrations (25 and 50 μM) markedly improving the plant's physiological stability. In fruits, both DS and JA application enhanced TPC, TAC, anthocyanins, and TSS. Conversely, in fruit, DS increased weight loss, which was less pronounced during fruit sprayed with JA. The beneficial effects of JA, especially in higher JA concentrations, were also observed in both years, mainly under severe DS (FC40 and FC20), highlighting its crucial role in the improvement of mechanisms related to plant tolerance under water deficit. These results accentuate the effectiveness of JA in improving the physiological and biochemical responses of pomegranate under DS and provide an affordable alternative for sustainable management of crops in arid and semi-arid areas.