Mitigating salinity stress in Moringa oleifera through seaweed-derived biostimulants

Climate change, food scarcity, salt stress, and a rapidly growing population are just a few of the significant global challenges. In arid and semi-arid regions worldwide, salt stress is a significant negative factor that can reduce seed germination and seedling growth, ultimately leading to decreased plant growth and crop productivity. Seaweed extracts are used as nutrient supplements or biofertilizers in agriculture to increase plant growth and yield. In this study, we examined the beneficial effects of foliar applications of seaweed extracts from Turbinaria ornata and Actinotrichia fragilis on the growth and performance of Moringa oleifera under salt stress (up to 300 mM) in a greenhouse. Exposure of Moringa to salinity stress resulted in an overall decrease in growth and the contents of chlorophyll a, chlorophyll b, carotenoids, and soluble sugars, versus an increase in phenolic content. However, foliar application of A. fragilis and T. ornata extracts significantly improved the growth and physiology of Moringa under salt stress, with T. ornata exhibiting greater effectiveness. This study demonstrates that seaweed-based biofertilizers can enhance plant productivity while reducing reliance on chemical inputs, offering a sustainable and environmentally friendly alternative for agriculture.