Silicon attenuates the physiological and biochemical damage induced by waterlogging in cowpea (Vigna unguiculata L. Walp)

Waterlogging is an environmental constraint that limits cowpea (Vigna unguiculata L. Walp.) productivity by inducing root hypoxia and oxidative stress. In this context, the objective was to evaluate the potential of exogenous silicon (Si) application to mitigate the negative impacts of waterlogging on the physiological, biochemical, and biometric performance of cowpea. The experiment was conducted in a completely randomized design, in a 2x3 factorial scheme, combining two water conditions (field capacity and waterlogging) and three silicon doses (0, 100, and 200 mg L⁻¹). Waterlogging significantly restricted gas exchange, leaf area, and biomass accumulation. However, the application of 100 mg L⁻¹ Si proved effective in maintaining leaf area and optimizing dry matter accumulation under waterlogging conditions. Silicon supplementation potentiated the activity of antioxidant enzymes (SOD and CAT) and increased proline levels, reducing electrolyte leakage and preserving membrane integrity. Silicic acid acts as a critical modulator of abiotic stress, conferring greater resilience to cowpea by attenuating damage caused by root hypoxia. Silicon supplementation is a viable and efficient biotechnological strategy to enhance cowpea resilience in areas prone to seasonal waterlogging, thereby preserving physiological integrity and optimizing water-use efficiency under stress.