Abstract
• Background and Aims: In seeds with deep simple epicotyl morphophysiological dormancy, warm and cold stratification are required to break dormancy of the radicle and shoot, respectively. Although the shoot remains inside the seed all winter, little is known about its growth and morphological development prior to emergence in spring. The aims of the present study were to determine the temperature requirements for radicle and shoot emergence in seeds of Viburnum betulifolium and V. parvifolium and to monitor growth of the epicotyl, plumule and cotyledons in root-emerged seeds. • Methods: Fresh and pre-treated seeds of V. betulifolium and V. parvifolium were incubated under various temperature regimes and monitored for radicle and shoot emergence. Growth of the epicotyl and cotyledons at different stages was observed with dissecting and scanning electron microscopes. • Key Results: The optimum temperature for radicle emergence of seeds of both species, either kept continuously at a single regime or exposed to a sequence of regimes, was 20/10 °C. GA3 had no effect on radicle emergence. Cold stratification (5 °C) was required for shoot emergence. The shoot apical meristem in fresh seeds did not form a bulge until the embryo had grown to the critical length for radicle emergence. After radicle emergence, the epicotyl-plumule and cotyledons grew slowly at 5 and 20/10 °C, and the first pair of true leaves was initiated. However, the shoot emerged only from seeds that received cold stratification. • Conclusions: Seeds of V. betulifolium and V. parvifolium have deep simple epicotyl morphophysiological dormancy, C1bB (root)-C3 (epicotyl). Warm stratification was required to break the first part of physiological dormancy (PD), thereby allowing embryo growth and subsequently radicle emergence. Although cold stratification was not required for differentiation of the epicotyl-plumule, it was required to break the second part of PD, thereby allowing the shoot to emerge in spring.
Original language | English |
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Pages (from-to) | 13-22 |
Number of pages | 10 |
Journal | Annals of Botany |
Volume | 108 |
Issue number | 1 |
DOIs | |
State | Published - Jul 2011 |
Bibliographical note
Funding Information:The authors thank Wei-Lien Chen, Ta-Yuan Chien, Huei-Ping Huang, Alice Wu, Yen-Wei Chang, Chang-Yen Chen, Wen-Yu Hsu and Kai-Chun Yang for technical assistance. This research was supported by grants NSC 99-2628-B-054-001-MY3 to C.-T.C., NSC 89-2311-B-002 – 063 to L.-L.K.-H. and 99AS-8.1.2-F1-G1 to C.-T.C.. We thank the National Science Council (NSC) and the Council of Agriculture, Executive Yuan, Taiwan, for this support.
Keywords
- Epicotyl morphophysiological dormancy
- Viburnum
- epicotyl-plumule growth
- radicle emergence
- seed germination
- shoot growth
ASJC Scopus subject areas
- Plant Science