Classification of Seed Dormancy in <i>Pedicularis hallaisanensis</i> Hurusawa: An Endemic and Endangered Species Native to Korea

Abstract

Pedicularis hallaisanensis Hurusawa, native to Mt. Halla and Gaya, is an endangered endemic species. To support conservation efforts, this study investigated its germination characteristics and kind of seed dormancy. The seeds of P. hallaisanensis had fully developed linear embryos at dispersal, with no additional embryo growth observed. Water imbibition was observed prior to germination. The seeds were water-permeable. The seeds did not germinate at four temperature treatments (4 °C/1 °C, 15 °C/6 °C, 20 °C/10 °C, and 25 °C/15 °C). However, cold stratification and gibberellic acid treatments broke seed dormancy. Total germination was 15%, 15%, and 45% at 12, 16, and 20 weeks of cold stratification, respectively. Total germination at 25 °C /15 °C for GA treatments were 0%, 25%, 25%, and 80% at 500, 1000, 1500, and 2000 mg/L, respectively. This study showed that the seeds of P. hallaisanensis have intermediate physiological dormancy, requiring 20 weeks of cold stratification or more than 2000 mg/L GA concentration to maximize total germination. These results are useful for understanding ecophysiological mechanisms related to the species’ habitat and for mass propagation to conserve this endangered species.

Keywords

• ecophysiological
• final germination rate
• mass propagation
• cold stratification
• seed morphology