ISHS Acta Horticulturae 718: III International Symposium on Models for Plant Growth, Environmental Control and Farm Management in Protected Cultivation (HortiModel 2006)
MODELING THE EFFECT OF NUTRIENT SOLUTION COMPOSITION AND IRRADIANCE ON ACCUMULATION OF NITRATE IN HYDROPONIC LETTUCE |
| Author: | M.P.N. Gent |
| Keywords: | carbohydrate, cytoplasm, feedback, homeostasis, membrane transport, metabolism, vacuole |
| Abstract:
Nitrate supply and electrical conductivity (EC) affect tissue composition of lettuce (Lactuca sativa L.) grown in hydroponic solution. Solution EC or nitrate plays a more dominant role in determining tissue nitrate under low compared to high irradiance. EC may affect nitrate in tissue because nitrate may play a role in regulating plant water potential. A model was developed to simulate this complex dependence of nitrate uptake, based on use of the vacuole as a storage compartment to maintain homeostasis of metabolites in the cytoplasm of cells. Feed-forward and feed-back responses were included in kinetic equations of simplified transport and metabolic reactions leading from photosynthesis and nitrate reduction to protein and structure. This sort of kinetic model could predict the dependence on irradiance and solution composition of tissue nitrate in lettuce, as well as the time course of various metabolite concentrations over a diurnal cycle and over several days. | |
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