[Responses of rice genotypes with different silicon uptake efficiency to different silicon supply]

To understand the effects of silicon on the growth and development of rice roots, a hydroponic experiment with 3 levels of silicon, i.e., no silicon (T1), 1.25 mmol silicon x L(-1) (T2), and 2 mmol silicon x L(-1) (T3), was conducted, using rice cultivars TN1 and Baixiangjing with high silicon uptake efficiency and Juanyejing and Hitomebore with low silicon uptake efficiency as test materials. The results showed that with the increase of silicon supply, the root dry mass, root-shoot ratio, lateral root number, and total root length of all test rice cultivars decreased, while the dry mass of above-ground parts, root number, and root diameter increased. Relatively higher silicon supply was beneficial to the differentiation and development of indefinite roots, but not favorable to the lateral roots. Under lower silicon supply, the root dry mass and root-shoot ratio of TN1 and Baixiangjing were significantly higher than those of Juanyejing and Hitomebore. Furthermore, the number of lateral roots and the total root length of Baixiangjing were also significantly higher than those of Juanyejing and Hitomebore. It was concluded that total root length and lateral root number were the main factors affecting rice silicon uptake efficiency.