Role of Seaweed Biostimulant in Plant Growth and Stress Resistance - A Review

Modern agriculture must boost food production while reducing environmental harm. Traditional inputs like synthetic pesticides and fertilizers degrade soil and ecosystems. Plant biostimulants, especially those from seaweed, offer a sustainable alternative by enhancing natural plant functions. Rich in phytohormones, polysaccharides, amino acids, and minerals, seaweed extracts improve growth, photosynthesis, and nutrient uptake. Brown Seaweed Extract (BSE) acts as a synergistic potent biostimulant in vegetable cropping systems, for physiological enhancements and improved yields that stimulate root and shoot development, improve nutrient and water uptake, and enhance photosynthetic efficiency, collectively strengthening plant metabolism and stress resilience, withstanding fluctuations in water availability, temperature, and salinity. Its effects include enhanced root growth and nutrient uptake, allowing vegetables to better utilize soil resources and potentially reduce dependence on synthetic fertilizers. They also strengthen plant defenses against abiotic stresses (drought, salinity, heat) and biotic threats (pests, diseases) by activating antioxidants, stress proteins, and systemic resistance. BSE-induced hormonal and metabolic priming improves the growth base, particularly in early phases. Crucially, it provides improved stress tolerance against climatic variables like drought, temperature extremes, and salinity, making it valuable under increasing climatic variability. Their multifaceted benefits make seaweed biostimulants a promising eco-friendly tool for resilient agriculture. This article reviews the need for continued research into their modes of action and standardized application protocols to fully harness their potential in creating more resilient and productive agricultural systems.