ISHS Acta Horticulturae 174: Symposium Greenhouse Climate and its Control
ENVIRONMENTAL EFFECTS ON PHOTOSYNTHESIS, SIMULATED AND EXPERIMENTAL RESULTS FROM A STUDY ON A "TOMATO-MINICROP" |
| Authors: | A.H.C.M. Schapendonk, P. Brouwer |
| Abstract:
In this study, the quantitative effects of temperature on photosynthesis and crop-growth are discussed. A realistic assessment of the problem requires knowledge about the various physiological parameters involved. The conceptual basis for the calculations is given by the approach of Farquhar et al. (1980). Their model includes Arrhenius equations for CO2 and O2 binding on RUBISCO, activation of this enzyme and the electron-transport rate with the associated synthesis of ATP and NADPH. The validity of the model was tested as a subset of a bigger crop-growth model. The main problem of predicting canopy photosynthesis is the quantification of the distribution and absorbtion of radiation by the canopy. To avoid this complication, photosynthesis and growth were measured on a "tomato mini-crop", that could be regarded as a small closed canopy from the start of the experiments on. The results of the measurements were used to validate the model. Changes of the actual leaf area index, the specific leaf area, the dry matter distribution and the chemical composition during a period of 7 days were used as external forcing functions. The results indicate that the temperature optimum for crop photosynthesis is rather flat. The data of the experiments were in agreement with the simulated photosynthetic rates. | |
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