Physiological, Productive, and Nutritional Performance of Tomato Plants Treated with Iron and Zinc Nanoparticles via Foliar Application Under Deficit Irrigation

Water deficit is a critical limiting factor for tomato plant development and productivity, reducing photosynthesis, membrane stability, fruit nutrient content, and yield. This study evaluated the efficacy of zinc oxide nanoparticles (ZnO NPs) and iron oxide nanoparticles (Fe₂O₃NPs), compared to their conventional forms (ZnSO₄·7H₂O and FeSO₄·7H₂O), in mit-igating water stress (50% ETc) under field conditions. Tomato (Solanum lycopersicum Mill.), hybrid HM 2798 was utilized as the experimental material. A split-plot field experiment was conducted with two irrigation levels (50% and 100% ETc) and five foliar treatments: Control (no application), FeSO₄·7H₂O (T1), Fe₂O₃NPs (T2), ZnONPs (T3), ZnSO₄·7H₂O (T4), with four replications. The water deficit significantly reduced the leaf area index, photo-synthetic rate, membrane stability, calcium and boron contents in fruits, and total and marketable yield. Foliar application of iron and zinc had a limited effect on tomato plant growth but increased the photosynthetic rate under both irrigation levels. Notable results included a 61% increase in total yield under full irrigation with ZnSO₄·7H₂O (T4), and a 117.3% increase in fruit iron content under water deficit with Fe₂O₃ NPs (T2). It is con-cluded that ZnSO₄·7H₂O was the most effective treatment in mitigating water stress, sug-gesting conventional zinc supplementation as a viable strategy to sustain tomato produc-tion under water restriction.