Abstract: The seed dormancy and seed germination characteristics of Kobresia littledalei in response to the application of NaOH and plant exogenous growth substances were studied in this experiment. The seeds were soaked into 20~40 g·L^-1 NaOH at different time intervals (1 h,2 h and 3 h) and also treated with 0~400 μmol·L^-1 of exogenous plant growth substances such as gibberellins (GA₃,GA₄₊₇),abscisic acid (ABA),flridone (FL) and paclobutrazol (PA). The results showed there was no imbibition barrier in the seeds of Kobresia littledalei. Seed germination percentage was significantly improved by treating seeds with 20 g·L^-1 NaOH for 2 h or using 30~40 g·L^-1 NaOH for 1 h (P<0.05). GA₄₊₇ of 50~200 μmol·L^-1,GA₃ of 200 μmol·L^-1 and FL of 200~400 μmol·L^-1 could promote seed germination,while ABA and high concentration of PA (≥200 μmol·L^-1) showed inhibition of seed germination. Except GA₃+FL,the exogenous plant growth substance combinations did not significantly increase seed germination percentage. It was confirmed that seeds of Kobresia littledalei had physiological dormancy which could be broken by treating the seeds with 40 g·L^-1NaOH for 1 h,which could increase the seed germination percentage up to 98%. In addition,plant exogenous growth substances could contribute in maintaining the viability of the embryo.

Key words: Kobresia littledalei, Seed dormancy, Seed germination, Plant exogenous growth substances

摘要： 为研究藏北嵩草（Kobresia littledalei C. B. Clarke）种子休眠与发芽的特性，采用浓度为20~40 g·L^-1 NaOH处理1，2，3 h及不同浓度（0~400 μmol·L^-1）的赤霉素（Gibberellin，GA₃，GA₄₊₇）、脱落酸（Abscisic acid，ABA）、氟啶酮（Fluridone，FL）和多效唑（Paclobutrazol，PA）等外源植物生长物质单独及两两混合后处理藏北嵩草种子。结果表明藏北嵩草种子不存在吸水障碍；20 g·L^-1NaOH处理2 h，30 g·L^-1，40 g·L^-1 NaOH处理1 h均可显著提高发芽率（P<0.05）；50 ~200 μmol·L^-1 GA₄₊₇，200 μmol·L^-1 GA₃，200~400 μmol·L^-1FL单独作用时对发芽有促进作用，而任何浓度ABA和高浓度PA（≥200 μmol·L^-1）则表现为抑制作用；除GA₃+FL处理外，植物生长调节剂互作处理都未显著提升发芽率。藏北嵩草种子属于生理性休眠；40 g·L^-1 NaOH浸种1 h可有效打破休眠，发芽率达98%；添加适宜浓度的GA₃，GA₄₊₇，ABA，FL，PA及GA₃+ABA、ABA+FL等外源植物生长物质均有利于保持藏北嵩草种胚的活性。

关键词: 藏北嵩草, 种子休眠, 种子发芽, 植物生长调节剂