Salicylic Acid Enhances Yield and Alleviates Drought-Induced Oxidative Damage in Two Carrot Cultivars with Contrasting Tolerance

The current study focused on evaluating the significance of salicylic acid (SA) on morpho-physiological and biochemical traits, including secondary metabolites in carrot (Daucus carota L.) leaves and roots under water stress. Carrot plants were exposed to water-limited conditions (60% field capacity) along with a control. An experiment was conducted in pots using two carrot cultivars, Maharani and T-29. After four weeks of seed germination, drought stress was imposed and maintained for 30 days. Both levels of SA (150 and 300 mg/L) were sprayed on carrot foliage in addition to the control (no spray). Plant samples were collected to analyze growth-related parameters after 15 days. The water deficit situation remarkably reduced plant growth, yield, and photosynthetic pigments. However, the level of proline, glycinebetaine, total phenolics and ascorbic acid increased in both the edible part (root) and leaves of the carrot plant. Meanwhile, levels of oxidative stress markers and antioxidant enzyme activities increased under water stress. However, SA supplementation improved plant growth and yield by protecting against osmotic stress and oxidative damage through the enhancement of antioxidants in edible roots and leaves. Among the two carrot cultivars, ‘Maharani’ performed better under water deficit conditions with SA application. The results suggest that the SA application can promote plant growth and yield under water stress and may serve as an effective approach to reduce stress-related harm to plants.