Improvement of Fruit Quality and Phytochemical Components of Pomegranate by Spraying with B₂O₃ and ZnO Nanoparticles

Pomegranate is one of the most important and widely distributed trees. Boron and zinc are important nutrients for plant growth and fruit quality. Nanotechnology has emerged as one of the most innovative scientific fields in agriculture. This study was conducted to describe the changes in the physiochemical characteristics (weight, diameter, length, firmness and color), as well as the phytochemicals attributes (total phenolics, total flavonoids, ascorbic acid, anthocyanin and antioxidant %) and minerals contents, of pomegranates fruits of the 'Wonderful' cultivar as a result of spraying pomegranate trees using nanomaterials (zinc oxide (ZnONPs) and boron oxide (B(2)O(3)NPs)). In three successive developmental stages (full bloom, 6 weeks after full bloom and one month before harvest time), the trees were sprayed with 0.25, 0.5 and 1 g/L ZnONPs, as well as 0.25, 0.5 and 1 g/L B(2)O(3)NPs during the 2021 and 2022 seasons. The application of ZnONPs and B(2)O(3)NPs influenced the qualitative characteristics of the fruits in the studied seasons. The highest marketable % was observed for the 0.50 and 1 g/L ZnONPs and 1 g/L B(2)O(3)NPs compared to the other treatments. Also, a positive effect was recorded for the ZnONPs and B(2)O(3)NPs on the fruits' physical properties. All of the ZnONP and B2O3NP treatments resulted in increasing the total phenolic, flavonoid, anthocyanin and ascorbic acid contents and the antioxidant activity in the pomegranate juices. In conclusion, our results suggest that spraying pomegranate trees with ZnONPs and B(2)O(3)NPs improves the marketable fruit, enhances the fruit quality and increases the bioactive components and antioxidant activity.