BACKGROUND

Esculin, a natural coumarin glucoside with antioxidant properties, is a secondary metabolite found in various plant species and has been traditionally valued for its medicinal benefits. This study focused on evaluating the ability of esculin to enhance flax plant tolerance to lead (Pb) toxicity.

METHODOLOGY

Flax plants were irrigated with either distilled water or a lead solution (200 mg/L) and subsequently treated with foliar sprays of esculin at concentrations of 0, 50, and 100 mg/L.

RESULTS

The findings revealed that esculin application significantly improved the plants’ resilience to Pb toxicity. It reduced the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and electrolyte leakage (EL), while improving the membrane stability index (MSI). Esculin effectively alleviated oxidative stress by boosting the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), phenylalanine ammonia-lyase (PAL), and tyrosine ammonia-lyase (TAL), in addition to increasing total phenols and proline content. Furthermore, esculin contributes to maintaining membrane integrity by reducing sodium (Na) uptake and increasing the absorption of potassium (K), magnesium (Mg), phosphorus (P), and calcium (Ca). It also minimizes Pb accumulation in the plants, further mitigating lead toxicity. These effects were associated with improved photosynthetic pigment concentrations, higher levels of soluble sugars (TSS), and an increase in free amino acids (FAA) under lead stress conditions. The application of esculin enhanced key agronomic traits, including shoot and root growth, fresh and dry biomass, seed yield per plant, and 1000-seed weight. Additionally, seed quality improved, with increased oil, carbohydrate, and protein content under Pb stress conditions.

CONCLUSION

In summary, esculin glycosides is a novel approach that effectively reduces lead toxicity and enhances stress tolerance in flax, offering a promising strategy for managing heavy metal stress in crops.