Effect of TiO2 NPs on the growth, anatomic features and biochemistry parameters of Baby sun rose (Aptenia cordifolia).

Rapid commercialization, industrialization and the use of nanotechnology has led to an increase in the distribution of nanoparticles (NPs) in the environment. The most common metal oxide NPs which is present within products is Titanium dioxide (TiO2). TiO2 NPs have photocatalytic nature and can affect plant growth. The current study investigated the morphological, anatomical and biochemical features of Baby sun rose (Aptenia cordifolia) after exposure to different concentrations of TiO2 nanoparticles (0, 1, 5, 10 and 20 mg L-1). Treatment with TiO2 NPs showed changes in the morphological features and increased photosynthetic pigmentation within the plant. An increase in the level of phenolics (12%) and flavonoid compounds (13%) was observed when plants were treated with moderate levels of TiO2 NPs. A reduction in the diameter of the vascular bundles and increased thickening of the transverse wall were observed in several samples. The number of scattered vascular bundles in the stems increased. The morphological, biochemical, and anatomical responses of Baby sun rose indicates that plants can adapt to environments contaminated with up to 20 mg L-1 TiO2 NPs. The cultivation of Baby sun rose plants in environments polluted with TiO2 NPs is recommended. This study enhances the knowledge of the effect of TiO2 NPs on the growth of Baby sun rose which is an ornamental plant, widely cultivated in different regions of Iran. The results of this study suggest that contaminated environments up to 20 mg L-1 TiO2 NPs can be managed by phytoremediation. Further studies are needed to investigate this plant's tolerance strategies against stress caused by TiO2 NPs and bulk TiO2 as well as the effect of other nanoparticles on plant. © Prof. H.S. Srivastava Foundation for Science and Society 2021.