Effects of TiO-NPs pretreatment on UV-B stress tolerance in Arabidopsis thaliana.

As the ozone hole in the North and South poles continues to increase, the entire ecosystem will face an environmental crisis caused by enhanced UV-B radiation. Considering the function of TiO and the application of nanomaterials in agriculture, the effect of TiO-NPs on UV-B stress tolerance in Arabidopsis was investigated. The phenotype of plants was determined, and the expression patterns of antioxidant systems and related genes were analyzed. Modification of the antioxidant system and changes in the flavonoid content of plants were observed by histochemical staining. The effects of TiO-NPs and UV-B on mitosis were observed at the cellular level, and the degree of DNA damage was analyzed by the detection of CPDs content. The effects of TiO-NPs and UV-B on SOD isozymes were detected by SOD isozyme Native-PAGE electrophoresis. A laser confocal microscope was used to explore the protective mechanism of TiO-NPs against UV-B radiation. Results showed that pretreatment of TiO-NPs significantly alleviated the stress of UV-B radiation on plants. TiO-NPs activated the antioxidant system of plants, improved the activity of antioxidant enzymes, and promoted the synthesis of flavonoids. Moreover, TiO-NPs could effectively shield UV-B radiation to prevent the depolymerization of microtubules in plant cells. 10 mg/L of TiO-NPs is a safe and effective application dose, which has no biological toxicity to plants. Our research results reported for the first time that pretreatment of TiO-NPs could effectively alleviate UV-B stress to plants, providing new ideas for the application of nanomaterials in agriculture.