Amino acids as biostimulants: Roles in plant growth, nutrition, and stress tolerance; A comprehensive review

Abstract Amino acids have emerged as promising biostimulants in sustainable agriculture, supporting plant growth, stress tolerance, and nutrient efficiency. This review synthesizes current knowledge on their physiological roles, such as enhancing photosynthesis, antioxidant activity, and hormonal regulation, and application methods like foliar spraying and fertigation. Widely effective across crops, amino acids also aid micronutrient uptake through chelation. However, challenges remain, including inconsistent product quality and limited mechanistic understanding. Advances in omics, formulation technologies, and precision agriculture offer opportunities to maximize their potential in climate-resilient crop production.