RESEARCH ARTICLE https://doi.org/10.7235/HORT.20190067 Deep Simple Epicotyl Morphophysiological Dormancy in Seeds of Gymnospermium microrrhynchum (S.Moore) Takht., a Rare Species in Korea Yong Ha Rhie1†, Seung Youn Lee2†, and Ki Sun Kim3,4* 1Department of Horticulture and Forestry, Pai Chai University, Daejeon 35345, Korea 2Division of Horticulture & Medicinal Plant, Andong National University, Andong 36792, Korea 3Department of Horticultural Science and Biotechnology, Seoul National University, Seoul 08826, Korea 4Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea *Corresponding author:
[email protected] † These authors contributed equally to the work. Abstract 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 Received: March 5, 2019 following year, shoot emergence began in late March and completed in April. In the laboratory Revised: June 10, 2019 experiments, seeds at 15/6°C (light 12 h/dark 12 h) had 87% germination within 20 weeks, while Accepted:October 7, 2019 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.