Abstract: The objectives of this study were to prepare a nutrient solution with iron tailing silicon-selenium nanoparticles and to provide theoretical basis for enhancing rice growth and selenium assimilation. A two-factorial experiment was conducted using rice cultivar Daohuaxiang No. 2, with four levels of silicon (0, 300, 600, 900 g·hm^-2) and four levels of selenium nanoparticles (0, 18.75, 37.5, 56.25 g·hm^-2). Additionally, a control group using sodium selenite (37.5 g·hm^-2) and silicon (600 g·hm^-2) was included. This experiment was established to examine the impacts of silicon and selenium nanoparticle concentrations in the nutrient solution on the growth and selenium accumulation in rice seedlings, determine the optimal silicon-selenium ratio, and elucidate the role of silicon in selenium enrichment and its underlying physiological mechanisms. Results showed that the concurrent application of silicon and selenium synergistically enhanced rice growth compared to treatments with only selenium or silicon. Silicon addition facilitated the growth of rice seedlings by increasing the activities of superoxide dismutase (SOD) and catalase (CAT). The nutrient solution containing 600 g·hm^-2 of silicon and 37.5 g·hm^-2 of selenium nanoparticles markedly outperformed other treatment groups, increasing plant height and root-to-shoot ratio of rice seedlings by 9.9% and 5.3%, respectively; and the selenium content in roots, stems and leaves increased by 41.4%, 32.4% and 42.3% respectively, compared to the sodium selenite-treated group.

Key words: nano selenium nutrient solution, iron tailing, rice seedling, enzyme activity, selenium content