Journal of Experimental Agriculture International

Drought stress is a major constraint on crop growth and productivity because it disrupts plant water relations, photosynthesis, mineral nutrition and cellular redox balance. Cerium oxide nanoparticles (CeO₂ NPs), also known as nanoceria, have received attention as potential agents for mitigating these effects. This review examines the physicochemical properties of nanoceria, its principal application routes and the physiological, biochemical and molecular mechanisms associated with plant responses to water deficit. Surface oxygen vacancies and Ce³⁺/Ce⁴⁺ redox cycling contribute to the enzyme-mimetic activity of nanoceria and its interactions with reactive oxygen species. The reviewed studies describe responses following seed priming, foliar application and root or soil exposure. Evidence from sorghum, mungbean, barley, rice, grapevine, apple and wheat indicates that suitable nanoparticle concentrations may reduce oxidative damage, enhance antioxidant defences, protect photosynthetic functions and improve plant water status. Reported responses also include osmolyte accumulation, greater membrane stability, changes in mineral nutrient homeostasis and altered expression of drought-responsive genes. However, these outcomes depend on the crop species, nanoparticle concentration, application method and severity of water deficit. Higher concentrations may produce adverse effects, and findings from composite formulations cannot always be attributed to unmodified nanoceria. Limited field validation, incomplete understanding of root-level responses and unresolved questions about cerium accumulation in edible tissues restrict immediate agricultural application. Further evaluation is necessary to determine the consistency, practical relevance and safety of nanoceria-mediated drought responses.