Green synthesis of functionalized CuO, ZnO and Fe₂O₃ nanoparticles using medicinal plant extracts for early seedling growth evaluation

Abstract

Abstract Phytochemical compounds are among the most widely used natural materials and have attracted much attention in recent years in various fields and industries. In biological applications, they can be used as preservatives and antifungals. This study investigated the effect of micronutrients on the growth of flaxseed cultivar Golchin and rapeseed cultivar X using a culture medium containing medicinal plant extracts and three metal oxide nanoparticles. Zinc oxide (ZnO), copper oxide (CuO), and iron oxide (Fe₂O₃) nanoparticles were synthesized using Aloe barbadensis Miller leaf extract, Gundelia tournefortii L extract, and Punica granatum L. extract, respectively, and were characterized by FESEM, XRD, EDX, FTIR, and TGA analyses. Different concentrations (0, 15, 62, 125, 250, and 500 mg/L) of each nanoparticle were evaluated for the germination of flaxseed and rapeseed. The results showed that functionalized ZnO and CuO nanoparticles accelerated the increase in root and shoot length, whereas Fe₂O₃ nanoparticles exhibited only limited effects. Specifically, in flaxseed of the Golchin cultivar, functionalized ZnO nanoparticles at 500 mg/L increased root and shoot length by up to 80–100% compared to the control after four days. In rapeseed cultivar X, functionalized ZnO nanoparticles at 500 mg/L produced a comparable enhancement (up to 80–100%), whereas functionalized Fe₂O₃ nanoparticles at 500 mg/L did not show a significant growth increase for either seed type. The effects of Aloe barbadensis Miller and Punica granatum L. extracts at concentrations of 1, 2, 3, and 4% were also tested. Punica granatum L. extract exhibited inhibitory effects, while Aloe barbadensis Miller extract noticeably slowed bud development and reduced growth rate.