ISHS Acta Horticulturae 395: Dormancy and the related Problems of Deciduous Fruit Trees
CONVERSION OF BOUND TO FREE WATER IN ENDODORMANT BUDS OF APPLE IS AN INCREMENTAL PROCESS |
| Authors: | M. Faust, D. Liu, M.J. Line, G.W. Stutte |
| Keywords: | Magnetic resonance imaging, Malus domestica, Apple, Dormancy, Chilling |
| Abstract:
The amount of bound versus free water in vegetative buds of apple (Malus domestica Borkh.) was estimated throughout the endodormant period by magnetic resonance imaging in the low chill-requiring cultivar, ‘Anna’ and the high chillrequiring cultivar ‘Northern Spy’. Proton density and T2 images were obtained and the number of voxels with T2 relaxation times between 15 and 25 milliseconds was determined. ‘Anna’ and ‘Northern Spy’ buds had limited water in this range before chilling exposure, indicating that most of the tissue water was in the bound state. During chilling the incidence of T2 times in the 15 to 25 ms range gradually increased to 82% in ‘Anna’ and 81% in ‘Northern Spy’ after chilling. However, this increase in the percentage of free water required 400 hours of chilling in ‘Anna’ buds, whereas those of ‘Northern Spy’ required 3000 h. The conversion of bound to free water was incremental during chilling. | |
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