地涌金莲种子形态生理休眠及激素的动态变化

Morphophysiological Dormancy and Changes of Endogenous ABA and GA_4Contents in Seeds of Musella lasiocarpa

珍稀植物地涌金莲在野外能产生大量的种子,但成熟的种子散布后不能顺利地转化为幼苗。在暖层积(25℃)过程中,蘑菇形的小胚逐渐分化与生长,6个月后,胚已形态成熟且能很好地萌发;同时,胚内激素ABA含量不断下降,GA_4含量显著增加,且与胚的形态成熟和萌发力的增强密切相关。这些结果充分证实地涌金莲种子具有形态生理休眠——在很大程度上限制了野外种子萌发。此外,种子不萌发可能与生境长时间干旱胁迫有关。

Rare Musella lasiocarpa can naturally produce many seeds that don＇t develop into seedlings after shedding. The mushroom-shaped small embryos without obvious differentiation would gradually differentiate and grew in the process of warm stratification at 25 ℃. After 6-month warm stratification, the embryos matured and could germinate well. At the same time, endogenous ABA constantly decreased and however, GA4 markedly increased over time, which was significantly associated with embryo growth and germinability （R2=0.97）. Thus, the results fully confirmed that seeds of this species are morphological dormancy, which restricts the germina- tion ofM. lasicocarpa seeds to a great extent in the wild. Also, the phenomenon that the seeds cannot germinate in the habitat is closely related with long drought stress in a dry season.