The Investigation of TiO 2 NPs Effect as a Wastewater Treatment to Mitigate Cd Negative Impact on Bamboo Growth

The recent emerging evidence reveals that titanium dioxide nanoparticles (TiO 2 NPs) can be used as a wastewater treatment. This study provides new information about the possible detoxification role of TiO 2 NPs as a wastewater treatment in plants under heavy metal stress, with an emphasis on the mechanisms involved. Here, we investigated the effects of TiO 2 NPs as one wastewater treatment on a bamboo species ( Arundinaria pygmaea L.) under in vitro Cadmium (Cd) toxicity conditions. A factorial experiment was conducted in a completely randomized design with four replications of four concentrations of Cd (50, 100, 200, and 300 µM) alone and in combination with 100 and 200 µM TiO 2 NPs as two wastewater treatments, as well as a control treatment. The results indicated that TiO 2 NPs concentrations enhanced enzymatic and non-enzymatic antioxidant activities and proline accumulation as well as reducing hydrogen peroxide (H 2 O 2 ), superoxide radical (O 2 •− ), and malondialdehyde (MDA) levels, which led to improved photosynthetic parameters with an eventual increase in plant biomass as compared to the control treatment. Therefore, TiO 2 NPs improved the photosynthetic parameters of bamboo under Cd toxicity, which led to an increase in plant biomass. We concluded that the wastewater treatments of TiO 2 NPs improved bamboo biomass through the scavenging of reactive oxygen species (ROS) compounds (H 2 O 2 and O 2 •− ), which was induced by the stimulation of the antioxidant capacity of the plant. TiO 2 also protected cell membranes by reducing lipoperoxidation in bamboo under Cd toxicity. The concentration of 200 µM TiO 2 NPs had the most impact in reducing Cd toxicity.