Morpho-physiological impacts of esculin on enhancing rice tolerance to drought stress

Esculin is a coumarin glucoside that acts as an antioxidant secondary metabolite found in numerous plant species. The present study investigates the impact of esculin on rice plant growth under drought and well-watered environments. Rice (Oryza sativa L.) grains of the cultivar Giza 177 were soaked for two hours in water (control) or esculin (50, 100 and 150 ppm). All rice seedlings were subjected to drought stress 20 days post-sowing. After two weeks, the data indicated that treatment with esculin effectively enhanced the drought tolerance of rice plants, particularly at 150 ppm. This improvement was associated with elevated ascorbic acid, proline and various secondary metabolites accumulation alongside a marked decline in primary metabolites. Esculin enhanced the antioxidant capacity of rice under drought stress, as evidenced by elevated total ascorbic acid peroxidase, antioxidant capacity and decreased malondialdehyde levels. Conversely, esculin diminished the activity of polyphenol oxidase enzymes under drought-stress conditions.