Investigation of toxicity of zinc oxide nanoparticles synthesized by olive extract on growth and pigments in Borago officinalis

The synthesis of metal nanoparticles has attracted the attention of scientists in various fields, particularly in the chemical, physical, biological and medical sciences. Using extract of plant for nanoparticle synthesis can be advantageous over other biological processes because it eliminates the elaborate process of maintaining cell cultures and can also be suitably scaled up for large-scale nanoparticle synthesis. In this study, zinc oxide (ZnO) nanoparticles were successfully synthesized from ZnNO3 using Olive (Olea europaea).  Nanoparticles were characterized with the help of Transmission electron microscopy (TEM) and UV–Visibe absorption spectroscopy. To study the effects of zinc oxide (ZnO) nanoparticles (0, 200, 400 ppm) on growth, proline and Malondialdehyde (MDA), total phenol, flavonoid, Hydrogen peroxide (H2O2), chlorophylls and anthocyanin content in plant of Borago officinalis, experiment was carried out at shahid bahonar university of Kerman University in 2014. Synthesised ZnO nanoparticles were confirmed by the absorption maxima at the wavelength of 370 nm. TEM image revealed that ZnO nanoparticles were spherical with average size 41 nm. Results showed the plants that treated with zinc oxide (ZnO) nanoparticles, increased root and shoot length. But soluble suger, anthocyanin and CAT activity in the plants that treated with zinc oxide (ZnO) nanoparticles had no significant effect. On the other hand, Zinc oxide (ZnO) nanoparticles decreased proline and chlorophyll content. In addition, ZnO nanoparticles treatment at 400 ppm increased phenol content, H2O2, lipid peroxidation and APX, GPX, PAL activity. Reactive oxygen species generation was a toxicological mechanisms of nanoparticles that increased H2O2 content and lipid peroxidation in plants. ZnO nanoparticles causing increased production of reactive oxygen species and decreased proline and chlorophyll content in Borago officinalis.