Effects of titanium dioxide nanoparticles (TiO2) on germination and seedling growth of Vitex plants (Vitex agnus-castus L.)

Different concentrations of nanoparticles impose impact different effects on germination and plant growth. The purpose of this study was to investigate the effects of 11 different concentrations of titanium dioxide nanoparticles on germination and seedling growth characteristics of Vitex plant (Vitex agnus-castus L.). This experiment was conducted in the laboratory of the Islamic Azad University of Tehran in 2018 as a completely randomized design with 4 replications. The measured traits included germination percentage, relative germination percentage, germination rate, mean germination time, germination index, weighted germination index, vigor seedling index, fresh and dry weight of seedling and root and shoot length. XRD measurements showed that the titanium dioxide nanoparticles used in the anatase form were present. The results showed that the highest germination percentage (80%), relative germination percentage (115%), germination rate (22.37), germination index (190), weighted germination index (2.30), vigor seedling index (541) and fresh weight (0.52) were observed through application of 200 μg.ml-1 titanium nitric oxide. Higher concentrations of nano titanium dioxide had no positive effect on germination indices. The response index also showed that nano-titanium dioxide at all concentrations had a stimulatory effect on mean germination time, root length, shoot length and dry weight but only at 200 mg.l-1 treatment had a stimulatory effect on germination percentage and germination rate. The results of this study indicated that the treatment of 200 μg.ml-1 titanium dioxide nanoparticles had the most positive effect on germination and seedling growth factors of Vitex plantlets.