2019 ASHS Annual Conference

A traditional medicinal plant, coastal glehnia (Glehnia littoralis Fr. Schmidt ex Miquel) is a valuable perennial herb, distributed on the east and west coasts of South Korea. It belongs to the Umbelliferae, which have been known to have a morpho-physiological dormancy (MPD). In this study, we aimed to find conditions for breaking dormancy and increasing the germination rate of coastal glehnia. Cold and/or warm stratifications (5℃ or 25℃ for 8 weeks, 5℃ and 25℃ for 4 weeks each) were used to break dormancy in growth chambers. For wet cold treatment, the seeds were stored at 5℃ with wet gauze for 8 or 10 weeks. After then, the pericarps of cold-treated seeds for 10 weeks were removed and placed on petri dishes, which were incubated in growth chambers with five different constant air temperatures (5, 10, 15, 20, and 25℃) for 25 days. To examine the germination inhibitory effect of pericarps, the extracts of seeds with pericarps, seeds and pericarps were treated on lettuce seeds and the seed germination rate was investigated for 7 days. The cold stratification (5℃) for 8 weeks showed 11% of germination rate but the other stratifications had the germination rate of less than 2%. The ratio of embryo to seed was 1.6 times higher than that of dry seeds at 8 weeks of wet cold treatment. Removal of pericarps increased the germination rate; the final germination rate under 15℃ and 20℃ were 68% and 65%, respectively. The mean germination time (MGT) and time to reach 50% of germination (T₅₀) were significantly the shortest at 20℃ among the treatments. Extracts of pericarps were ineffective to inhibit germination rate of lettuce seeds suggesting the absence of germination-inhibiting compounds in the pericarps. These results concluded that seeds of coastal glehnia have a MPD and wet cold treatment for 8 weeks and removal of pericarps before germination under 15℃ or 20℃ are required to break dormancy and increase germination rate of coastal glehnia.