Zinc Oxide Nanoparticles Enhanced Biomass and Zinc Content and Induced Changes in Biological Properties of Red <i>Perilla frutescens</i>

The above-ground parts of plants, including leaves, constitute an important part of a human diet. Their mineral and biological composition can be modified by proper preparation of the soil substrate, i.e., supplying it with nutrients. The objective of this study was to assess the influence of zinc oxide nanoparticles (ZnO NPs) at 0, 50, 100 and 200 mg L−1 concentrations on red perilla (Perilla frutescens var. crispa f. purpurea) leaf yield and quality. Plants were grown in 2 L pot under a plastic greenhouse condition. The exposure to ZnO NPs increased leaf fresh and dry weight and leaf Zn content as compared with untreated control. Fresh weight boost was the most pronounced at 50 mg L−1 ZnO NPs. The lowest concentration of ZnO NPs also enhanced the content of total polyphenols, antioxidant activity, and antiradical activity. Treatments with 50 or 100 mg L−1 ZnO NPs boosted the level of total anthocyanins and bacteriostatic activity of 25% extracts. Overall, this study demonstrated that ZnO NPs at low rates is useful as a biostimulant and nanofertilizer for red perilla production