2019 ASHS Annual Conference
Seed Dormancy and Germination Responses to Temperatures in Seeds of Eight Veronica Species Native to Korea
Seed Dormancy and Germination Responses to Temperatures in Seeds of Eight Veronica Species Native to Korea
Tuesday, July 23, 2019: 2:15 PM
Montecristo 3 (Tropicana Las Vegas)
Korea National Arboretum has been conducting the project ‘Wild Flowers’ for the commercialization of wild flowers native to Korea. In this project, we have selected Korean native Veronica species as new ornamental potted or landscape plants. Firstly, we investigated the seed germination characteristics of eight Korean native Veronica species (V. dahurica, V. rotunda, V. kiusiana var. diamantiaca, V. pusanensis, V. rotunda var. subintegra, V. nakaiana, V. pyrethrina, and V. kiusiana var. glabrifolia), and seed dormancy types (kinds) of the seeds were classified. Among the study species, V. kiusiana var. diamantiaca has been designated as both an endemic and rare species (critically endangered) and V. pusanensis is endemic species in Korea. The seeds were incubated at constant temperatures of 4, 15, 20, 25, and 30°C for 30 days, and germination percentages were calculated. Embryo morphology was observed in initial seed and at just before germination. The optimum germination temperatures of the seeds of the eight Veronica species were approximately 20 to 25°C. Although the seeds of V. rotunda and V. kiusiana var. diamantiaca germinated to 66.1% and 47.6%, respectively, the seeds of the other Veronica species germinated to more than 90% at five temperature regimes for 30 days, The embryo length inside the seeds increased by 18.8 to 58.0% of their initial length. To promote the germination of V. kiusiana var. diamantiaca seeds, we treated the seeds with different periods of cold stratification (0, 3, and 6 weeks at 4°C) and gibberellic acid (GA3) soaking (0, 50, 100, and 1,000 mg·L-1). The seeds of V. kiusiana var. diamantiaca germinated to 45.0, 75.3, and 80.3%, respectively, following 0, 3, and 6 weeks of cold stratification. The seeds of of V. kiusiana var. diamantiaca germinated to 44.7, 71.3, 87.2, and 91.7%, respectively, following the soaking treatment of different concentrations of GA3 (0 [control], 50, 100, and 1,000 mg·L-1). There were different types of seed dormancy (MD and MPD) within the eight Veronica species examined; thus, we found an interspecific variation in seed germination traits in the genus. The results could be useful to study the morphological seed dormancy and ecophysiological mechanisms of the genus Veronica.