Effect of drought stress on cuticular lipids in leaves of black bambara groundnut (Vigna subterranea)

Abstract

Plants have developed multiple adaptive strategies to withstand drought stress, one of which is the accumulation of cuticular waxes that enhance resistance to water loss. This study investigated the impact of drought stress on the cuticular lipid composition of leaves in a black Bambara groundnut landrace. The experiment was conducted in a screen house using a completely randomized design. Plants were subjected to water deficit, and leaf samples were collected at 3, 6, 9, and 12 days of stress, followed by a recovery phase where irrigation was resumed for one week, with additional sampling at 3 and 6 days after re-watering. Soil physicochemical and elemental characteristics were analyzed, alongside measurements of relative water content (RWC) and cuticular lipid extraction. Wax components were identified using gas chromatography–mass spectrometry (GC-MS). The soil was predominantly sandy (79.36%) with low nutrient content, pH 6.2, and minimal organic carbon and sodium. Drought stress significantly reduced RWC from 98.03% to 76.63% (p < 0.05). GC-MS results revealed alkanes and esters as the main wax constituents. Overall, the findings indicate that drought induces an increase in cuticular lipid accumulation, which plays a protective role in minimizing water loss under stress conditions.