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medfate (version 0.7.4)

photo: Photosynthesis submodel functions

Description

Set of functions used in the calculation of photosynthesis.

Usage

photo.GammaTemp(leaf_temp)
photo.KmTemp(leaf_temp, Oi = 209)
photo.VmaxTemp(Vmax298, leaf_temp)
photo.JmaxTemp(Jmax298, leaf_temp)
photo.electronLimitedPhotosynthesis(Q, Ci, GT, Jmax)
photo.rubiscoLimitedPhotosynthesis(Ci, GT, Km, Vmax)
photo.photosynthesis(Q, Catm, Gc, leaf_temp, Vmax298, Jmax298, verbose = FALSE)
photo.leafPhotosynthesisFunction(E, Catm, Patm, Tair, vpa, u, 
                             absRad, Q, Vmax298, Jmax298, Gwmin, Gwmax,
                             leafWidth = 1.0, refLeafArea = 1, verbose = FALSE)
photo.sunshadePhotosynthesisFunction(E, Catm, Patm, Tair, vpa, 
                                     SLarea, SHarea, u, 
                                     absRadSL, absRadSH, QSL, QSH, 
                                     Vmax298SL, Vmax298SH, Jmax298SL, Jmax298SH, 
                                     Gwmin, Gwmax, leafWidth = 1.0, verbose = FALSE)
photo.multilayerPhotosynthesisFunction(E, Catm, Patm, Tair, vpa, 
                                      SLarea, SHarea, u, 
                                      absRadSL, absRadSH, QSL, QSH, 
                                      Vmax298, Jmax298, Gwmin, Gwmax, leafWidth = 1.0, 
                                      verbose = FALSE)

Arguments

leaf_temp

Leaf temperature (in <U+00BA>C).

Oi

Oxigen concentration (mmol*mol-1).

Vmax298, Vmax298SL, Vmax298SH

Maximum Rubisco carboxylation rate per leaf area at 298<U+00BA>K (i.e. 25 <U+00BA>C) (micromol*s-1*m-2) (for each canopy layer in the case of photo.multilayerPhotosynthesisFunction). 'SH' stands for shade leaves, whereas 'SL' stands for sunlit leaves.

Jmax298, Jmax298SL, Jmax298SH

Maximum electron transport rate per leaf area at 298<U+00BA>K (i.e. 25 <U+00BA>C) (micromol*s-1*m-2) (for each canopy layer in the case of photo.multilayerPhotosynthesisFunction). 'SH' stands for shade leaves, whereas 'SL' stands for sunlit leaves.

Q

Active photon flux density (micromol * s-1 * m-2).

Ci

CO2 internal concentration (micromol * mol-1).

GT

CO2 saturation point corrected by temperature (micromol * mol-1).

Jmax

Maximum electron transport rate per leaf area (micromol*s-1*m-2).

Km

Km = Kc*(1.0+(Oi/Ko)) - Michaelis-Menten term corrected by temperature (in micromol * mol-1).

Vmax

Maximum Rubisco carboxylation rate per leaf area (micromol*s-1*m-2).

Catm

CO2 air concentration (micromol * mol-1).

Gc

CO2 leaf (stomatal) conductance (mol * s-1 * m-2).

E

Transpiration flow rate per leaf area (mmol*s-1*m-2).

Patm

Atmospheric air pressure (in kPa).

Tair

Air temperature (in <U+00BA>C).

vpa

Vapour pressure deficit (in kPa).

u

Wind speed above the leaf boundary (in m/s) (for each canopy layer in the case of photo.multilayerPhotosynthesisFunction).

absRad

Absorbed long- and short-wave radiation (in W*m^-2).

leafWidth

Leaf width (in cm).

refLeafArea

Leaf reference area.

Gwmin, Gwmax

Minimum and maximum leaf water conductance (i.e. cuticular and maximum stomatal conductance) (mol * s-1 * m-2).

verbose

Boolean flag to indicate console output.

SLarea, SHarea

Leaf area index of sunlit/shade leaves (for each canopy layer in the case of photo.multilayerPhotosynthesisFunction).

absRadSL, absRadSH

Instantaneous absorbed radiation (W<U+00B7>m-2) per unit of sunlit/shade leaf area (for each canopy layer in the case of photo.multilayerPhotosynthesisFunction).

QSL, QSH

Active photon flux density (micromol * s-1 * m-2) per unit of sunlit/shade leaf area (for each canopy layer in the case of photo.multilayerPhotosynthesisFunction).

Value

Values returned for each function are:

  • photo.GammaTemp: CO2 compensation concentration (micromol * mol-1).

  • photo.KmTemp: Michaelis-Menten coefficients of Rubisco for Carbon (micromol * mol-1) and Oxigen (mmol * mol-1).

  • photo.VmaxTemp: Temperature correction of Vmax298.

  • photo.JmaxTemp: Temperature correction of Jmax298.

  • photo.electronLimitedPhotosynthesis: Electron-limited photosynthesis (micromol*s-1*m-2) following Farquhar et al. (1980).

  • photo.rubiscoLimitedPhotosynthesis: Rubisco-limited photosynthesis (micromol*s-1*m-2) following Farquhar et al. (1980).

  • photo.photosynthesis: Calculates gross photosynthesis (micromol*s-1*m-2) following (Farquhar et al. (1980) and Collatz et al (1991).

  • photo.leafPhotosynthesisFunction: Returns a data frame with the following columns:

    • LeafTemperature: Leaf temperature (<U+00BA>C).

    • LeafVPD: Leaf vapor pressure deficit (kPa).

    • WaterVaporConductance: Leaf vapor conductance (mol * s-1 * m-2).

    • Photosynthesis: Gross photosynthesis (micromol*s-1*m-2).

    • NetPhotosynthesis: Net photosynthesis, after discounting autotrophic respiration (micromol*s-1*m-2).

  • photo.sunshadePhotosynthesisFunction and photo.multilayerPhotosynthesisFunction: Return a data frame with the following columns:

    • Photosynthesis: Gross photosynthesis (micromol*s-1*m-2).

    • NetPhotosynthesis: Net photosynthesis, after discounting autotrophic respiration (micromol*s-1*m-2).

Details

Details of the photosynthesis submodel are given in a vignette.

References

Bernacchi, C. J., E. L. Singsaas, C. Pimentel, A. R. Portis, and S. P. Long. 2001. Improved temperature response functions for models of Rubisco-limited photosynthesis. Plant, Cell and Environment 24:253<U+2013>259.

Collatz, G. J., J. T. Ball, C. Grivet, and J. A. Berry. 1991. Physiological and environmental regulation of stomatal conductance, photosynthesis and transpiration: a model that includes a laminar boundary layer. Agricultural and Forest Meteorology 54:107<U+2013>136.

Farquhar, G. D., S. von Caemmerer, and J. A. Berry. 1980. A biochemical model of photosynthetic CO2 assimilation in leaves of C3 species. Planta 149:78<U+2013>90.

Leuning, R. 2002. Temperature dependence of two parameters in a photosynthesis model. Plant, Cell and Environment 25:1205<U+2013>1210.

Sperry, J. S., M. D. Venturas, W. R. L. Anderegg, M. Mencuccini, D. S. Mackay, Y. Wang, and D. M. Love. 2016. Predicting stomatal responses to the environment from the optimization of photosynthetic gain and hydraulic cost. Plant Cell and Environment.

See Also

hydraulics.supplyFunctionNetwork, biophysics.leafTemperature, spwb