Abstract: Inter subspecific hybrid rice Ⅱyou 2070, Ⅱyou 419 and their restorer lines 2070 and Zhong 419 were used to analyze root system growth, root exudates and amount of root produced cytokinins during different growth stages. Results showed that hybrid rice combinations had root growth heterosis and strong root exudates, with higher zeatin content and total amount of cytokinins in root exudates than those of their restorer lines. Strong root activity in hybrid rice combinations was related to slow decrement in zeatin content and total amount of cytokinins.

Key words: inter subspecific hybrid rice, root system, root exudates, cytokinin

摘要： 以亚种间杂交组合Ⅱ优2070及恢复系2070、Ⅱ优419及恢复系中419为材料，分析测定了在不同生育期水稻的根系生长、伤流液量及根源细胞分裂素含量的变化情况，结果表明亚种间杂交组合具有根系生长优势和较强的伤流强度，根系伤流液中玉米素及细胞分裂素总量高于恢复系，杂交组合根系活力强，与玉米素及细胞分裂素总量下降缓慢有关。

关键词: 亚种间杂交稻, 根系, 伤流液, 细胞分裂素