ISHS Acta Horticulturae 184: I International Symposium on Computer Modelling in Fruit Research and Orchard Management
CARBOHYDRATE BALANCE MODELS FOR 'MONTMORENCY' SOUR CHERRY LEAVES, SHOOTS AND FRUITS DURING DEVELOPMENT |
| Authors: | E.M. Kappes, J.A. Flore |
| Abstract:
Photosynthesis and respiration were measured and modelled for leaves, whole shoots and fruits of sour cherry during leaf area expansion, shoot elongation and fruit growth respectively. At the same time with a comparable set of plants, leaf, shoot and fruit growth were measured and correlated to carbohydrate contents. Leaf, shoot and fruit carbohydrate accumulation was modelled. These models were combined in a BASIC computer program to estimate carbohydrate fixation, accumulation, import and export for the various organs at different times and time periods during their development. Assuming photosynthesis and growth rates measured in 1984, it could be estimated that carbohydrate net export started after 3, 4, and 17 days for the seventh and, the terminal leaf, and the shoot respectively, at a leaf size of 10.6 and 9.2cm2 and a shoot length of 16cm. While the absolute size at the start of net export was similar, the percentage of full expansion was 17 and 51 for the seventh and the terminal leaf respectively. The onset of export seems to depend on the leaf position. It was also estimated that fruits produced 11.2% of their required carbohydrate. During stages I, II, and III of fruit development fruits produced 19.4, 29.7 and 1.5% of the carbohydrate used during the respective period. This shows the importance of fruit photosynthesis during its early development when leaf area is still small. Respiration was estimated to use 30.9% of the total carbohydrates required. During stages I, II, and III the share of respiration was 32.7, 70. 9, and 19.9%. The increased need for respiration during stage II is thought to be caused by lignification and lipid synthesis during pit hardening and embryo development. | |
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