Effect of Silica-Based Nanomaterials on Seed Germination and Seedling Growth of Rice ( Oryza sativa L.).

The application of nanomaterials (NMs) in agriculture has become a global concern in recent years. However, studies on their effects on plants are still limited. Here, we conducted a seed germination experiment for 5 days and a hydroponics experiment for 14 days to study the effects of silicon dioxide NMs(nSiO 2 ) and silicon carbide NMs(nSiC) (0,10, 50, 200 mg/L) on rice ( Oryza sativa L.). Bulk SiO 2 (bSiO 2 ) and sodium silicate (Na 2 SiO 3 ) were used as controls. The results showed that nSiO 2 and nSiC increased the shoot length (11-37%, 6-25%) and root length (17-87%, 59-207%) of germinating seeds, respectively, compared with the control. Similarly, inter-root exposure to nSiO 2 , bSiO 2, and nSiC improved the activity of aboveground catalase (10-55%, 31-34%, and 13-51%) and increased the content of trace elements magnesium, copper, and zinc, thus promoting the photosynthesis of rice. However, Na 2 SiO 3 at a concentration of 200 mg/L reduced the aboveground and root biomass of rice by 27-51% and 4-17%, respectively. This may be because excess silicon not only inhibited the activity of root antioxidant enzymes but also disrupted the balance of mineral elements. This finding provides a new basis for the effect of silica-based NMs promotion on seed germination and rice growth.