Abstract: Kolkwitzia amabilis Graebn , an endangered plant endemic to China ,is listed in China Rare and Endangered plant list. We studied morphology characters of seeds by scanning electron microscope and paraffin slice, measured seeds absorbing water, detected biotic of methanol extract of pericarp and endosperm, analysied the effect of sulphuric acid, GA₃ and cold stratification treatment on breaking seed dormancy. The result showed: a) The hard pericarp is the main reason for Kolkwitzia amabilis' mechanical dormancy. b) Germination inhibitor exist in endosperm may the cause of physiology dormancy, stratification or GA3 treatment can break the seed dormancy effectively. c) The best way to break seed dormancy is that treat the seed by sulphuric acid for fifteen minutes, then soaking in 400 mg·L-1 GA₃ solution; or stratificating in 4 ℃ about 30 days.

Key words: Kolkwitzia amabilis Graebn, fruit, dormancy, sulphuric acid, GA₃, cold stratification