不同硅吸收效率水稻品种根系对硅素水平的响应

为明确硅对水稻根系生长发育的影响，以4个硅吸收效率不同的水稻品种（高效吸收品种TN1、白香粳和低效吸收品种卷叶粳、一目惚）为材料，采用国际水稻研究所的营养液配方水培试验，设置0(T₁)、1.25 (T₂)和2 (T₃) mmol·L^-1 3个硅素水平，研究了不同硅素水平对不同基因型水稻根系和地上部干物质量、根条数、侧根数、根总长和根直径等的影响.结果表明：随硅素水平的提高，水稻各品种均表现为根系干物质量、根冠比、侧根数和根总长逐渐减少，地上部干物质量、根条数和根直径逐渐增大.较高的硅素水平有利于水稻不定根的分化发育，而不利于侧根的分化发育.在较低的硅素水平下，硅吸收效率高的基因型水稻TN1和白香粳的根干物质量和根冠比显著高于硅吸收效率低的品种卷叶粳和一目惚，其中白香粳的侧根数和根总长均显著高于卷叶粳和一目惚.可见，根总长和侧根数是引起水稻硅素吸收差异的主要原因.

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 (T1), 125 mmol silicon·L-1 (T2), and 2 mmol silicon·L-1 (T3), 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.