Abstract: In pot culture and field experiment, the biological efficacy of soaking rice seed in S-07(S-3307, Uniconazol) and MET(PP₃₃₃) solution were studied. The results showed that the biological activity of S-07 is higher than that of MET as much as 10 folds. The biological efficacy of seed soaking in S-07 solution is higher than that of spraying on rice seedling and soil drenching with S-07, respectively. The growth rate of rice seedling was reduced with S-07 treatment and growth of rice seedling was not inhibited. The biological efficacy of S-07 has shown a strong retardent activity to control rice seedling growth, but promoted root and tiller growth of rice seedling, increased dry weight and root/shoot ratio of rice seedling. Light, temperature and soil moisture could affect the biological efficacy of S-07 on rice seedling.

Key words: Chemical control, Rice seedling, Uniconazol, Paclobutrazol, biological efficacy

摘要： 烯效唑和多效唑浸种对稻苗生长的影响比较研究表明，烯效唑的生物活性约比多效唑高10倍，然而喷苗或土施均降低烯效唑的生物活性。烯效唑浸种对稻苗的影响主要是降低稻苗生长的速率而不是抑制生长，因此，烯效唑是一种植物生长延缓物质．而不是植物生长抑制物质。烯效唑的生物学效应是控制稻苗的高度，促进根系生长、增加干重积累、促进分蘖、提高根冠比。 光、温及土壤水分条件会影响烯效唑的生物效应。

关键词: 秧苗, 烯效唑, 生物学效应, 化学控制, 植物生长调节剂