This article is an Advance Online Publication of the authors’ corrected proof. Note that minor changes may be made before final version publication.
The Horticulture Journal Preview doi: 10.2503/hortj.MI-104
The Japanese Society for JSHS
Horticultural Science
http://www.jshs.jp/
Effects of Temperature on Seed Germination and Photoperiod on Seedling Growth of Hosta yingeri S.B.Jones Hyun Jin Kim, Sun Hee Choi** and Yoon Jin Kim* Department of Horticulture, Biotechnology and Landscape Architecture, Seoul Women’s University, Seoul 01797, Korea
The aims of this study were to examine the effects of different temperatures on seed germination and initial long-day (LD) or short-day (SD) duration on growth, floral initiation, and development of Hosta yingeri S.B.Jones. The germination percentage of H. yingeri seeds was > 90% at 5°C and between 15°C–30°C. The lowest time to the first germination (TFG) and the mean germination time (MGT) were observed at around 30°C. The optimum temperature for germination can be around 30°C considering the final germination percentage, TFG, and MGT together. Plant height, number of leaves, and leaf length increased as the initial SD duration decreased. The percentages of plant bearing buds were 50%, 50%, 20%, 10%, and 0% when the initial SD treatments were 0, 3, 6, 9, and 12 weeks with 29, 26, 23, 20, and 17 weeks of LDs, respectively. No plants flowered when they were exposed to the initial LD conditions. Flower spike length, number of visible buds, and number of open flowers increased as the duration of the initial SD decreased. Four-week-old H. yingeri required ≥ 26 weeks of LD duration to achieve > 50% flowering. Key Words: cultivation, flowering, growth, Korean endemic plant, light.
Introduction Hosta species are distributed in East Asia and Russia, but most species have been found in China, Japan, and Korea (Lee and Maki, 2015). Hosta yingeri S.B.Jones was discovered in 1985 in the Heuksan Archipelago, South Korea by Barry R. Yinger (Jones, 1989). Hosta yingeri is a Korean endemic plant, and is distinguished from other species of Hosta by its relatively thick, adaxially dark green leaves. A delicate raceme of flowers is spread evenly around the central axis of the inflorescence with 3-long and 3-short pairing stamens. Because its unique characteristics include short inflorescences and small flowers, this hosta has the potential to be developed as a commercial potting plant. Hosta yingeri has been generally available in the hosta trade, and has become a popular garden plant species internationally. However, its remote habitat and limited natural environment has slowed progress of research to develop H. yingeri as a commercial plant.
Received; August 8, 2015. Accepted; October 21, 2015. First Published Online in J-STAGE on December 10, 2015. This study was supported by a special research grant from Seoul Women’s University (2015). * Corresponding author (E-mail:
[email protected]). ** Co-corresponding author (E-mail:
[email protected]).
Hosta species are generally propagated by lateral shoot division or tissue culture (Feng et al., 2009; Wilson and Rajapakse, 2000). Because only a few shoots can be obtained from one taxon, satisfying the increased demand has been difficult. The rapid availability of high potential Hosta cultivars is in part due to the use of seeds as a means of commercial propagation. Optimum germination temperature differs by species, and is required for commercial propagation. Seed germination of H. sieboldiana occurs over a wide temperature range, from 10°C to 30°C, but is most rapid at 25°C and 30°C (Kanazawa et al., 2015). The optimum germination temperature of H. plantaginea is 25°C, but the germination percentage is very low (
