Effects of Zinc Oxide Nano-particles on Groundnut (Arachis hypogaea) Seedlings

Along with the rapid growth of nanoparticle consumption in various industries, concerns about the unknown effects caused by the presence of these materials in the natural environment and agricultural systems are being highlighted. Due to the growing trend of Nano Zinc Oxide Nanoparticle (ZnO-np) which is one of the most widely used nanoparticles being released into the environment, it has attracted the attention for more studies to be done on the effects of this nanoparticle on organisms. This study was carried out to investigate the phytotoxicity effect of ZnO-np on peanut seedlings in Murashige and Skoog medium (MS medium). The experimental treatments of this study include nine concentrations of ZnO-np (0, 10, 30, 50, 100, 200, 400, 1000, 2000 ppm) added to MS medium. Peanut seedlings were incubated for 3 weeks in optimum condition and after that, seedling characteristics such as length, wet and dry weight of root and shoot were measured and the water content of root and shoot were calculated. Results of this study showed that the root and shoot length of peanut seedlings were affected by ZnO-np exposure, in a way that root length in 50 ppm ZnO-np and higher concentrations was significantly lower than that of control treatment and the shortest shoot length was observed to be from 2000 ppm ZnO-np concentration treatment. Also, both the root and shoot wet weight decreased as the nanoparticle concentration increased. However, despite the decreasing root and shoot dry weight with increasing concentration, there was no significant difference. On the other hand, the root dry weight in 10 ppm ZnO-np was significantly higher than the peanut seedlings treated with more than 200 ppm ZnO-np.