BIOSTIMULANTS AS SUSTAINABLE TOOLS FOR SALT STRESS MITIGATION: MECHANISMS, SYNERGIES, AND EFFECTIVENESS

Abstract

Biostimulants have emerged as innovative and sustainable tools in modern agriculture to mitigate salinity stress, a major constraint on global crop productivity. Derived from diverse sources including seaweed extracts, plant extracts, humic substances, microbial inoculants, protein hydrolysates, and inorganic compounds, biostimulants enhance plant resilience by influencing physiological and biochemical processes. Key mechanisms include improving nutrient uptake, regulating ion homeostasis, activating antioxidant defense systems, and mitigating oxidative and osmotic stress. However, challenges such as lack of standardization, regulatory barriers, and insufficient understanding of long-term soil impacts hinder their widespread adoption. Recent evidence also highlights the promising potential of synergistic combinations of different biostimulants, which can amplify stress mitigation effects through complementary mechanisms. This review provides a comprehensive analysis of biostimulant classification, action mechanisms, and efficacy across crops, with a critical evaluation of research gaps and practical limitations. By addressing these challenges through interdisciplinary collaboration and advanced technologies, biostimulants can offer a scalable solution to enhance crop tolerance to salinity, reduce reliance on chemical inputs, and contribute to global food security and environmental sustainability.