Titanium dioxide nanoparticles TiO2 NPs in crop stress management: Mechanisms, applications, and abiotic stress mitigation

Abiotic stresses significantly reduce global crop productivity by impairing physiological, biochemical, and molecular functions. Nanotechnology, particularly titanium dioxide nanoparticles (TiO₂ NPs), has emerged as an innovative approach to enhance plant resilience under severe environmental conditions. This review synthesizes recent experimental findings on TiO₂ NP biosynthesis and their protective roles against major abiotic stresses, including drought, salinity, heavy metal toxicity, temperature extremes, and UV radiation. TiO₂ NPs regulate photosynthetic efficiency, nutrient balance, ROS homeostasis, strengthen enzymatic and non-enzymatic antioxidant defenses, stabilize cellular membranes, osmolytes accumulation, and stress-responsive gene expression, thereby enhancing stress tolerance. The synergistic applications of TiO₂ NPs with other nanoparticles, phytohormones, and biochar establish additional regulatory networks to manage abiotic stresses. Despite promising results, challenges remain regarding inconsistent formulations, dose-dependent toxicity, environmental interactions, and limited field-scale validation. Addressing these gaps through optimized formulations, omics-based mechanistic studies, and biosafety assessments will support the safe and effective integration of TiO₂ NP technology into sustainable crop production under changing climate conditions.