Using sequential digital images to study seed germination and dormancy

A sequential imaging system was developed to study seed germination and dormancy. Images were collected automatically at set time intervals as frequent as 30 min for up to 5 days using a flat-bed scanner interfaced with a computer. The system permitted individual seeds to be followed throughout germination and early seedling growth. Sequential still images were made into simple movie clips that exposed features of germination not easily seen in traditional germination studies. Using this system, we were able to followed imbibition patterns after scarification treatments in honeylocust (Gleditsia triacanthos L.) seeds with impermeable seed coats (physical dormancy). Imbibition movies clearly showed different patterns of water entry into the seed coat following acid vs. physical scarification. We also used the system to measure seedling growth in redbud (Cercis canadensis L.) embryos following chilling stratification to relieve endogenous physiological dormancy. The major difference between embryos isolated from non-chilled and chilled seeds was the time to initiate radicle growth. After growth was initiated, growth rates were similar for non-chilled and chilled seeds.