Light spectrum-mediated improved drought-resilient rootstock performance under drought stress in Okra genotypes

Introduction: Drought stress poses a major risk to global agriculture, particularly in arid and semi-arid regions with low crop yields. Okra (Abelmoschus esculentus L.), an underappreciated but nutritionally important crop, suffers from yield and quality reductions in response to water scarcity. Grafting has emerged as a practical technique for enhancing drought tolerance by fusing sturdy rootstocks with high-yielding scions. Furthermore, light quality directly affects stress adaptation by modulating plant physiological, biochemical, and proteomic responses. Thus, this study's goal is to maximize drought-resistant rootstock performance under various light spectrums.

Materials and Results: Two okra genotypes, NS 7772 and NS 7774, were evaluated in this study under drought stress and under two different light spectra: 100% white light and red–blue–white (R:B:W) LED. The improved drought tolerance of NS-7774 was demonstrated by infrared thermographic pictures, which showed a lower canopy temperature, an increased relative water content, decreased oxidative damage (MDA), and increased antioxidant enzyme activity. Thylakoidal proteomic profiling and 2D-SDS-PAGE demonstrated improved metabolic stability, demonstrating that NS 7774 under R:B:W retained photosynthetic protein complexes and produced stress-responsive polypeptides. SEM-EDAX provided additional confirmation of nutrient retention under stress. Multivariate analysis revealed that antioxidant activity, protein, and chlorophyll are all significant components that support resilience.

Conclusion: These findings demonstrate that, when combined with spectrum light alteration, grafting can significantly boost okra's tolerance to drought. Because of its remarkable performance under R:B:W light, NS 7774 may be cultivated in drought-prone locations.