Mechanisms of Abiotic Stress Mitigation in Plants Using Biologically Synthesized Nanoparticles. A review

Abstract

Abiotic stresses such as drought, salinity, extreme temperatures, and heavy metal toxicity significantly limit plant growth, productivity, and global food security. Conventional management strategies, including breeding, chemical amendments, and irrigation practices, often fail to provide sustainable and long-term protection. In recent years, biologically synthesized nanoparticles (NPs) have emerged as eco-friendly tools for enhancing plant tolerance to environmental stress. These biogenic nanoparticles, produced using plants, microbes, fungi, and algae, possess unique physicochemical and biocompatible properties that enable targeted interactions within plant systems. Their application improves antioxidant defense by enhancing the activity of enzymes responsible for reactive oxygen species scavenging, regulates stress-responsive genes, and increases photosynthetic efficiency under adverse conditions. Furthermore, biogenic nanoparticles promote osmolyte accumulation, nutrient uptake, and ion homeostasis, thereby strengthening plant resilience against salinity, drought, and heavy metal toxicity. Compared with chemically synthesized nanoparticles, biological synthesis offers advantages such as lower toxicity, environmental safety, and greater compatibility with plant tissues. This review summarizes the synthesis approaches, mechanisms of action, and recent advances related to the use of biogenic nanoparticles for mitigating abiotic stress in plants. Additionally, it highlights current knowledge gaps related to molecular interactions, environmental fate, and field-level validation. Future research priorities include integrating nano-enabled tools into sustainable agriculture, optimizing dosage and application methods, and evaluating long-term ecological impacts. Biologically synthesized nanoparticles represent a promising frontier for developing climate-resilient and resource-efficient agricultural strategies.