Seed germination ecophysiology of Jeffersonia diphylla, a perennial herb of mesic deciduous forests

Freshly-matured seeds of the mesic deciduous woodland herb Jeffersonia diphylla (Berberidaceae) have underdeveloped embryos and exhibit deep, simple morphophysiological dormancy. For rapid growth of the embryos at October (20/10°C) and November (15/16°C) temperatures in October and November, seeds must first be exposed to high (30/15°C) summer temperatures. If embryo growth is not completed in autumn, it continues during winter. However, even after 10-12 wk at summer temperatures, embryos grew very little at 5°C, unless growth already had begun at autumn temperatures. After embryo growth has been completed, or after it has been initiated, seeds require cold stratification (5°C) to overcome dormancy. Embryos must attain a minimum length of c 1 mm before seed dormancy can be broken by cold stratification. -from Authors