Modelling photosynthetic photon flux density and maximum potential gross photosynthesis |
| |
| Authors: | R J Ritchie |
| |
| Institution: | (1) USDA—Agricultural Research Service, Western Regional Research Center, Exotic and Invasive Weeds Research Unit, 800 Buchanan Street, Albany, CA 94710, USA;(2) Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064, USA;(3) Department of Environmental Physics & Meteorology, University of Athens, University Campus, Builds. PHYS-V, Athens, 15784, Greece;(4) Present address: Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH 03824, USA; |
| |
| Abstract: | Irradiance data software developed by the NREL Solar Radiation Laboratory (Simple Model of Atmospheric Radiative Transfer
of Sunshine, SMARTS) has been used for modelling photosynthesis. Spectra and total irradiance were expressed in terms of quanta mol m−2 s−1, photosynthetic photon flux density, PPFD (400–700 nm)]. Using the SMARTS software it is possible to (1) calculate the solar spectrum for a planar surface for any given solar elevation angle, allowing for the attenuating effects
of the atmosphere on extraterrestrial irradiance at each wavelength in the 400–700 nm range and for the thickness of atmosphere
the light must pass through during the course of a day, (2) calculate PPFD vs. solar time for any latitude and date and (3) estimate total daily irradiance for any latitude and date and hence calculate the total photon irradiance for a whole year
or for a growing season. Models of photosynthetic activity vs. PPFD are discussed. Gross photosynthesis (P
g) vs. photosynthetic photon flux density (PPFD) (P
g
vs. I) characteristics of single leaves compared to that of a canopy of leaves are different. It is shown that that the optimum
irradiance for a leaf (Iopt) is the half-saturation irradiance for a battery of leaves in series. A C3 plant, with leaves having an optimum photosynthetic rate at 700 μmol m−2 s−1 PPFD, was used as a realistic worked example. The model gives good estimates of gross photosynthesis (P
g) for a given date and latitude. Seasonal and annual estimates of P
g can be made. Taking cloudiness into account, the model predicts maximum P
g rates of about 10 g(C) m−2 d−1, which is close to the maximum reported P
g experimental measurements. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
