Cerium oxide nanoparticles priming enhances aged safflower seed vigor via improved photosynthetic and antioxidant capacity

Safflower seeds, a commonly used traditional Chinese medicinal material, are highly susceptible to aging due to their high oil content, which severely impairs the quality and yield of safflower. Cerium Oxide Nanoparticles (CeO 2 NPs) priming has emerged as an innovative technique to improve seed physiological performance. Nevertheless, the underlying mechanisms by which CeO 2 NPs priming enhances the vigor of aged safflower seeds remain poorly elucidated. CeO 2 NPs increased the germination percentage of aged safflower seeds from 64.5% to 87.4%, and markedly elevated seedling biomass and chlorophyll content. Physiological measurements demonstrated that CeO 2 NPs exerted prominent effects in reducing reactive oxygen species (ROS) accumulation and enhancing antioxidant enzyme activities. Lipidomic results indicated that CeO 2 NPs obviously raised the contents of membrane lipids such as DGDG and SQDG, thereby facilitating the repair of membrane damage in aged safflower seeds. Transcriptomic analysis revealed that CeO 2 NPs significantly upregulated genes related to light-harvesting proteins. Furthermore, qPCR verification confirmed that the expression levels of genes involved in sugar metabolism, fatty acid metabolism, antioxidant system and light-harvesting protein synthesis were distinctly upregulated. This study shows that CeO 2 NPs can enhance the vigor of aged safflower seeds by promoting the photosynthetic capacity and improving the antioxidant capacity.