目的 探究光照、温度和干旱胁迫对藏药川西小黄菊Tanacetum tatsienense种子萌发的影响。方法 在5个不同温度（15、20、25、30、35℃）下，设置2个光照条件（光照12 h/黑暗12 h、连续黑暗24 h）和5个聚乙二醇浓度（0、5%、10%、15%、20%）对川西小黄菊种子进行萌发实验，对种子萌发率、平均萌发时间、萌发指数、幼叶长、胚轴长、胚根长等指标进行统计分析。结果 光照、温度和干旱胁迫对川西小黄菊种子萌发具有显著影响（P<0.05）；同一温度下，光照条件下的种子萌发率和萌发指数大于黑暗条件，黑暗环境下平均萌发时间增加；20、25℃下光照对种子的萌发率和平均萌发时间影响不显著；15、30和35℃时，连续黑暗环境显著抑制种子的萌发率（萌发率最低仅为6.0%）和平均萌发时间（P<0.05）；15、20、25℃时随PEG浓度升高，种子萌发率和萌发指数减小、平均萌发时间增加，最短时间仅需3.4 d，最长时间达10.6 d；30、35℃时，低浓度PEG（≤10%）胁迫下萌发率和萌发指数显著大于对照（P<0.05），最高萌发率可达85.5%；幼叶和胚轴长度在所有温度下随PEG浓度的增加而缩短，胚根长度除15℃的所有温度下随PEG浓度增加呈先增长后缩短趋势，15℃时呈缩短趋势；回收后种子最终萌发率在15、20、25℃与对照无显著差异（P>0.05），在30、35℃时显著降低（P<0.05）。结论 温度改变会影响光照和干旱胁迫川西小黄菊种子适应性，是调节种子萌发的主要因素，而光照不是必要条件；另外，川西小黄菊种子PEG干旱胁迫承受阈值为20%，在轻度胁迫（PEG浓度0～10%），温度为20～30℃时种子萌发最好，在20～25℃时幼苗生长较好，可为川西小黄菊人工育苗提供参考。

Objective To explore the effects of light, temperature and drought stress on the seed germination of the Tibetan medicine Tanacetum tatsienense. Methods Under five different temperatures (15, 20, 25, 30, 35℃), two light conditions (light 12 h/darkness 12 h, continuous darkness 24 h) and five polyethylene glycol (PEG) concentrations (0, 5%, 10%, 15%, 20%) were set to conduct germination experiments on the seeds of T. tatsienense. The seed germination rate, average germination time, germination index, young leaf length, hypocotyl length and radicle length were statistically analyzed. Results Light, temperature and drought stress had significant effects on the seed germination of T. tatsienense (P < 0.05). At the same temperature, the germination rate and germination index of the seeds under light conditions were higher than those under dark conditions, and the average germination time increased under dark conditions. Light has no significant effect on the germination rate and average germination time of seeds at 20 and 25℃ (P > 0.05), while continuous dark environment inhibited significantly the germination rate (the lowest germination rate was only 6.0%) and the average germination time of seeds at 15, 30 and 35℃ (P < 0.05). With the increase of PEG concentration at 15, 20 and 25℃, the seed germination rate and germination index decreased and the average germination time increased, the shortest time was only 3.4 d, and the longest time was 10.6 d. At 30 and 35℃, the germination rate and germination index under low concentration PEG (≤ 10%) stress were significantly higher than the control (P < 0.05), the highest germination rate can reach 85.5%. The length of young leaves and hypocotyls decreased with the increase of PEG concentration at all temperatures, and the length of radicle increased first and then decreased with the increase of PEG concentration at all temperatures except 15℃, and decreased at 15℃. The final germination rate of the recovered seeds had no significant difference with the control at 15, 20 and 25℃ (P > 0.05), but decreased significantly at 30 and 35℃ (P < 0.05). Conclusion Research and analysis found that temperature changes can affect the adaptability of T. tatsienense seeds under light and drought stress. Temperature is the main factor to regulate its germination process, while light is not the necessary condition for its germination. In addition, the tolerance threshold to drought stress is 20%. Under mild stress (PEG concentration 0%-10%), the seeds germinated best at 20-30℃, and the seedlings grow better at 20-25℃. Therefore, this study can provide a reference for artificial seeding culivation of Tanacetum tatsienense.

R286

国家重点研发计划课题项目（2019YFC1712302）；国家重点研发计划课题项目（2019YFC1712305）