凹叶木兰(Magnolia sargentiana)是中国特有的观赏树木,种群的自然更新很差,须阐明其原因。研究发现,凹叶木兰种子的胚很小,无论是否被植物生长调节剂预处理,在冷层积(4℃)和暖层积(15℃)过程中,胚在种子内逐渐生长发育成熟,并能在多个温度下萌发,以变温30℃/20℃为适宜。由此可见,凹叶木兰种子不能萌发的直接原因是形态休眠。此外,凹叶木兰种子较耐脱水,但干燥脱水至含水量为7.1%和5.3%时,种子的存活率分别是78.3%和40%。保存6个月后,含水量为9.4%或7.1%的种子在–20℃下全部失活,而在0和4℃下的种子,存活率无显著变化,充分证实凹叶木兰种子是中间性的。 Magnolia sargentiana (Magnolia sargentiana) is a unique ornamental trees in China, the natural regeneration of the population is poor, to elucidate the reason. The results showed that embryos of Magnolia sieboldii were very small. Embryos gradually grew and matured in the seeds during cold stratification (4 ℃) and warm stratification (15 ℃), regardless of whether they were pretreated with plant growth regulators. And can germinate at multiple temperatures, in order to change the temperature 30 ℃ / 20 ℃ as appropriate. Thus, the direct reason for the non-germination of Magnolia grandiflora seeds is morphological dormancy. In addition, the seeds of Magnolia sieboldii were more resistant to dehydration, but the seed survival rates were 78.3% and 40%, respectively, after drying and dewatering to 7.1% and 5.3% water content. After six months of storage, seeds with a water content of 9.4% or 7.1% were all inactivated at -20 ° C, while there was no significant change in the survival of the seeds at 0 and 4 ° C, demonstrating that C. gracilis seeds are intermediate of.