Deep Simple Epicotyl Morphophysiological Dormancy in Seeds of Gymnospermium microrrhynchum (S.Moore) Takht., a Rare Species in Korea

Gymnospermium microrrhynchum is an herbaceous perennial plant in the Berberidaceae family and is a vulnerable species in Korea. We examined the embryo growth and germination of G. microrrhynchum in terms of temperatures under both outdoor and laboratory conditions. G. microrrhynchum seed consisted of an underdeveloped embryo. The embryo grew at moderate temperatures in autumn after high summer temperatures, and the radicle emergence occurred in November. However, there was a delay in shoot emergence after radicle emergence and the shoot appeared after the end of winter. Radicle-emerged seeds required winter-season temperatures for seedling emergence. In the following year, shoot emergence began in late March and completed in April. In the laboratory experiments, seeds at 15/6°C (light 12 h/dark 12 h) had 87% germination within 20 weeks, while seeds did not germinate at 25/15°C, 20/10°C, or 5°C. Following the radicle emergence, cold stratification (5°C) broke epicotyl dormancy and produce the shoot. Gibberellic acid (GA3) had no effect on the radicle emergence. Based on these results, seeds of G. microrrhynchum have deep simple epicotyl morphophysiological dormancy. This research is the first study to determine the morphophysiological dormancy type of the Gymnospermium genus. KCI Citation Count: 0