Effect of Abscisic acid and Selenium foliar sprays on drought mitigation in tomato (Solanum lycopersicum L.)

Abstract Abscisic acid (ABA) and Selenium (Se) have been reported to alleviate the effect of abiotic stress especially drought in several plant species. Thus, this study aimed to compare the influence of foliar spray of ABA (0 and 100 µM) and Se (0 and 50 µM) on tomato plants grown under simulated drought stress at 0% soil field capacity (SFA). The obtained results based on physiochemical and antioxidant mechanism involving defense enzymes such as catalase, superoxide dismutase, ascorbate peroxidase and glutathione reductase revealed that ABA was potentially restrained drought stress in tomato plants compared to Se. ABA treatment significantly improved the relative water content and chlorophyll levels of seedlings compared to control. This represents the essential role of ABA on stress retrieval under drought conditions. In addition, ABA treated plants unveiled less hydrogen peroxide compared to control plants. This indicates the enhanced antioxidant mechanisms in ABA treated plants which consequently neutralized the hydrogen peroxide. In contrast, proline level was decreased in treated plants compared to control showed the diminished oxidative stress which simultaneously reduced the accumulation of proline. Overall, ABA protected tomato seedlings from the drought induced oxidative stress and promoted plant growth and development. Therefore, the present study suggests that the ABA foliar spray is more preferable to enhance the vegetative growth of tomato plants under water deficit condition.