Seaweed Extract as a Potential Stimulant in Mitigating Abiotic Stress: A Comprehensive Review

Abiotic stresses such as drought, salinity, temperature extremes, heavy metal toxicity, and ultraviolet radiation are major constraints to global agricultural productivity, and their impacts are being intensified by climate change. Sustainable and eco-friendly solutions are therefore urgently needed to enhance crop resilience. Seaweed extracts (SWEs), obtained from marine macroalgae such as Ascophyllum nodosum, Ecklonia maxima, and Sargassum spp., have emerged as promising plant biostimulants due to their abundance of growth regulators, polysaccharides, antioxidants, amino acids, and minerals. These compounds act synergistically to enhance stress tolerance by regulating hormonal balance, activating antioxidant defense systems, improving osmolyte accumulation, maintaining ion homeostasis, stabilizing cellular membranes, and sustaining photosynthetic efficiency. Evidence from both controlled and field studies demonstrates that SWE application improves plant growth, yield, and quality under diverse stress conditions. However, challenges such as variability in extract composition, lack of standardization, and incomplete mechanistic understanding must be addressed to ensure consistent performance. For the scientific community, this review provides an integrated framework on the role of SWEs in mitigating abiotic stress, identifies critical research priorities, and highlights their potential as sustainable, multifunctional tools in climate-smart agriculture.