Seed dormancy and germination in Cardiocrinum giganteum var. yunnanense, a perennial herb in China with post-dispersal embryo growth

Seeds of Cardiocrinum giganteum var. yunnanense, which is native to China, has underdeveloped embryos when dispersed from parent plants that did not grow until the second autumn and winter after exposure to summer temperatures. Radicles and cotyledons emerged in late winter and spring. Thus, a 15-16 month period was required from dispersal to seed germination. Under laboratory conditions, this period could be shortened to 5-6 months in a 25 degrees C/15 degrees C (60 days) -> 15 degrees C/5 degrees C (60 days) -> 5 degrees C (60 days) temperature sequence. Based on dormancy-breaking requirements, the seeds have deep simple morphophysiological dormancy (MPD). This is practical knowledge for propagation of the species from seeds.