ISHS Acta Horticulturae 395: Dormancy and the related Problems of Deciduous Fruit Trees
INVOLVEMENT OF APICAL DOMINANCE IN WINTER DORMANCY OF APPLE BUDS |
| Authors: | M. Faust, D. Liu, S.Y. Wang, G.W. Stutte |
| Keywords: | Magnetic resonance imaging, Malus domestica, lipids, thidiuzoron |
| DOI: | 10.17660/ActaHortic.1995.395.4 |
| Abstract:
Experiments were designed to differentiate between paradormancy and endodormancy in winter dormant apple (Malus domestica Borkh.) buds. Apple shoots were collected in October, and some decapitated and stored at 4°C to satisfy their cold requirement. A low and a high chilling-requiring cultivar was used. Terminal buds required less chilling than did lateral buds when the terminal was intact. When terminal buds were removed, lateral buds required a similar amount of chilling as the terminal buds. Thidiazuron (TDZ) could trigger growth when about 2/3 of the chilling was satisfied. In ‘Northern Spy’, a high chilling-requiring cultivar, the uppermost lateral bud grew strongly and assumed the role of the removed terminal by inhibiting lateral growth below it. From our evidence and data available in the literature, we conclude that winter dormancy starts with paradormancy, continues with endodormancy and ends with paradormancy again. The requirements of low and high chilling-requiring cultivars are in both aspects of dormancy. High-chilling requiring cultivars appear to have a longer endodormant period and a stronger apical dormancy during the two paradormant periods. This view of dormancy will aid further research into the nature of endodormancy, which so far has eluded physiological explanation. | |
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