The present study was performed to investigate the response of strawberry cv. Ventana to different concentrations of cysteine-coated Fe3O4 nanoparticles under the hydroponic culture system. The experiment was conducted in a completely randomized design. The strawberry plants were treated with iron sulfate 6 mg.L-1 (as control) and cysteine-coated Fe3O4 iron nanoparticles at concentrations of 0.06 and 6 mg.L-1. The application of Fe3O4 nanoparticles at concentrations equal to and 100 times less than that of the conventional iron fertilizer resulted in an evident increase in the leaf and fruit Fe content of strawberry. Furthermore, chlorophyll pigments, total soluble carbohydrate, and total soluble protein increased with the implementation of cysteine-coated Fe3O4 nanoparticles with respect to the values for the conventional iron sulfate fertilizer. Moreover, the nanoparticles increased the dry weights of the root, crown, petiole, and leaf and total biomass with respect to those in the control. More importantly, the addition of iron nanoparticles to the nutrient solution to replace the conventional iron source led to an increase in yield. As a result, a significant positive relationship was observed between leaf iron content and yield. In addition, the strawberry plants treated with the nanoparticles exhibited improvements in total soluble solids, anthocyanin, flavonoid, phenol, and antioxidant capacity. It was concluded that cysteine-coated Fe3O4 nanoparticles at a concentration 100 times lower than that of conventional iron can be used not only for the nutrition of strawberry and the improvement of the vegetative and physiological traits, yield, and qualitative characteristics of the fruit but also for the production of iron-rich strawberry fruit.
