effect on germination and early growth characteristics in wheat plants (triticumaestivum l.) seeds exposed to tio2 nanoparticles

the present study was aimed to investigate the effects of titanium dioxide nanoparticles (nano-tio 2 ) on wheat ( triticumaestivum l.) plants cv. parsi. the experimental treatments included seven concentrations of nano- tio 2 (10, 100, 1000, 1200, 1500 and 1700 ppm nano-tio 2 and control (without any tio 2 ). the results showed that among the wheat germination indices, germination rate and weighted germination index were affected by tio 2 nanoparticles treatments. the lowest and the highest germination rate (16.7 vs. 11.1n.day -1 ) were obtained in control and 1000 and 1200 ppm concentration of nano- tio 2   treatments, respectively. these values for weighted germination index were (2.4 vs. 2.08) in 2000 ppm and control treatments respectively.  in addition, plumule and radicle length, seedling fresh weight and seedling vigor index were affected by nano- tio 2 concentrations, significantly. plumule and radicle lengths at 1200 ppm concentration of nano-tio 2 were higher than untreated control. this study shows that using of tio 2 nanoparticles in suitable concentration caused increasing of seed germination of wheat cv. parsiin comparison to control plants, otherwise low concentrations had inhibitory effects on wheat germination characteristics.