Effect of Different Concentrations of Titanium Dioxide Nanoparticles on Germination and Early Growth of Five Desert Plant Species

Aims: Studying the effects of nanoparticles on living organisms seems to be necessary, especially in plants as the first trophic level. Thus the phytotoxicity of different concentrations of nano-TiO۲ on five desert plant species was investigated in the present study. Materials & Methods: The phytotoxicity of different concentrations (۰, ۱۰, ۱۰۰, ۵۰۰, ۱۵۰۰mgl-۱) of nano-TiO۲ on five desert plant species of Halothamnus glaucus Botsch, Haloxylon aphyllum L., Nitraria schoberi L., Zygophyllum eurypterum Boiss. & Buhse, Halocnemum strobilaceum were investigated using seed germination percentage, radicle, and plumule elongation measurement. Experiments were conducted based on a completely randomized design with four replications. Findings: Outcomes of the study demonstrated that the application of nano-TiO۲ had no adverse effect on germination at low concentrations (up to ۵۰۰mgl-۱), it also increased the germination of H. aphyllum (۷۲ to ۸۸%). The concentration of ۱۵۰۰mgl-۱ had a negative effect on germination and radicle growth of three species of N. schoberi (decrease in germination from ۳۲ to ۲۰% and radicle length from ۱۳.۸۵ to ۱۰.۶۸cm), H. aphyllum (decrease in germination from ۷۲ to ۴۴% and radicle length from ۶.۱۰۵ to ۴.۰۳cm). Conclusion: Generally, in most plants, low concentrations of nano-Tio۲ did not significantly affect germination and seedling growth, but in high concentrations (۱۵۰۰mgl-۱) due to toxicity effect, germination and seedling growth were reduced. Therefore, in using nanoparticles, attention to dosage, which is useful and not causes toxicity, is significant.