The aim of this study was to reveal the alleviating effect of foliar pretreatment with TiO2-NPs （titanium dioxide nanoparticles） on the growth of wheat seedlings under UV-B stress. Using T.aestivum as material， the effects of leaf TiO2-NPs pretreatment on mitosis， DNA damage， antioxidant enzyme system， and antioxidant-related genes in the alleviation of UV-B stress were comprehensively studied at the cellular， physiological， biochemical， and genetic levels. The results showed that 10 mg·L-1 TiO2-NPs foliar pretreatment significantly alleviated the inhibition of wheat seedling growth under low-（5.04 kJ·m-2） and high-dose（10.08 kJ·m-2） UV-B stress conditions. After UV-B stress， plant height of TiO2-NPs-treated wheat seedlings increased by 44.71% and 127.43%， root length increased by 38.92% and 159.10%， fresh weight increased by 50.03% and 78.67%， and dry weight increased by 37.33% and 126.84%， respectively. The proportion of mitotic abnormalities in root tip cells of TiO2-NPs pre-treated wheat seedlings was only 39.57% and 28.63% under low and high doses of UV-B stress， respectively， and the CPDs content in cells decreased by 60.43% and 48.81%， respectively， compared with the control group. TiO2-NPs foliar pretreatment increased the flavonol content by 1.44 times and 1.53 times under low- and high-dose UV-B stress， respectively， significantly increased the expression of flavonol synthesis genes（CHS and CHI） and SOD， and improved the ROS scavenging ability of wheat seedlings. In conclusion， foliar pretreatment with 10 mg·L-1 TiO2-NPs significantly improved the activity of plant antioxidant system， reduced the ROS-caused damage on wheat plants， and improved the tolerance of plants to UV-B stress.
%U https://bbr.nefu.edu.cn/EN/10.7525/j.issn.1673-5102.2025.04.011