ISHS Acta Horticulturae 456: II Modelling Plant Growth, Environmental Control and Farm Management in Protected Cultivation
SIMULATION OF PHOTOSYNTHETIC RATE OF C3 AND C4 PLANTS UNDER LOW TOTAL PRESSURE |
| Authors: | K. Iwabuchi, Y. Ibaraki, K. Kurata, T. Takakura |
| Keywords: | Gas diffusion rate, Leaf photosynthesis model, Low pressure, Maize, Spinach |
| Abstract:
Total pressure is an important factor for accurate prediction of photosynthesis for plant production in space, because the gas diffusion coefficient is inversely proportional to the total pressure. In this study, for the purpose of growing plants in space, simple leaf photosynthesis models of C3 and C4 plants by Thornley, et al. (1990) were applied to spinach and maize to investigate the effects of low total pressure on net photosynthetic rate at constant O2 and CO2 partial pressures. For prediction of photosynthetic responses to low total pressure, stomatal and boundary layer resistances to CO2 were expressed as functions of total pressure. Net photosynthetic rate in spinach increased as total pressure decreased due to the increase in gas diffusion rate. In maize, there was little change in net photosynthetic rate caused by low total pressure. The net photosynthetic rate for maize reached saturation with CO2 at atmospheric conditions, and as a result, the enhancement in CO2 diffusion caused by low total pressure did not affect the net photosynthetic rate. These results indicated that low total pressure has more effect on C3 plants than C4 plants. In addition, calculations with the model predicted that the increase in net photosynthetic rate brought about by low total pressure could be enhanced by high light intensity for both C3 and C4 plants. | |
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