ISHS Acta Horticulturae 507: III International Workshop on Models for Plant Growth and Control of the Shoot and Root Environments in Greenhouses
MODELLING TOMATO FRUIT TRANSPIRATION UNDER GREENHOUSE |
| Authors: | C. Leonardi, A. Baille, S. Guichard |
| Keywords: | Model, Tomato, Fruit, Transpiration, Conductance, Greenhouse, VPD, Humidity |
| Abstract:
Fruit transpiration may vary according to growing and climatic conditions and plays a significant role in fruit water balance. To better understand and predict tomato fruit transpiration, measurements of the transpiration rate of shaded and non-shaded fruits were carried out under a wide range of climatic conditions. Linear models relating transpiration and either air VPD (VPDa) or fruit-to-air VPD (VPDfr-air) were proposed and their parameters were identified. The best fit was always obtained when using the explicative variable VPDfr-air. The model using VPDa as variable fits moderately well in the case of shaded fruits, but is not adequate for non-shaded fruits. Values of cuticular conductance, gc deduced from our measurements appeared to depend (i) on the growth-VPD regime and (ii) on the prevailing values of VPDfr-air. Our results suggest that, as for leaf transpiration, VPD between the evaporating surface and the air is the variable that drives the fruit transpiration rate, and that more realistic models could be based on the hypothesis of a variation of gc vs. VPD. | |
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