Non-deep physiological dormancy in seed and germination requirements of lysimachia coreana nakai

This study aimed to determine the type of seed dormancy and to identify a suitable method of dormancy-breaking for an efficient seed viability test of Lysimachia coreana Nakai. To confirm the effect of gibberellic acid (GA₃ ) on seed germination at different temperatures, germination tests were conducted at 5, 15, 20, 25, 20/10, and 25/15^◦ C (12/12 h, light/dark), using 1% agar with 100, 250, and 500 mg·L⁻¹ GA₃ . Seeds were also stratified at 5 and 25/15^◦ C for 6 and 9 weeks, respectively, and then germinated at the same temperature. Seeds treated with GA₃ demonstrated an increased germination rate (GR) at all temperatures except 5^◦ C. The highest GR was 82.0% at 25/15^◦ C and 250 mg·L⁻¹ GA₃ (4.8 times higher than the control (14.0%)). Additionally, GR increased after cold stratification, whereas seeds did not germinate after warm stratification at all temperatures. After cold stratification, the highest GR was 56.0% at 25/15^◦ C, which was lower than the GR observed after GA₃ treatment. We hypothesized that L. coreana seeds have a non-deep physiological dormancy and concluded that 250 mg·L⁻¹ GA₃ treatment is more effective than cold stratification (9 weeks) for L. coreana seed-dormancy-breaking.