AciC4: C4 Photosynthesis

In plantecophys: Modelling and Analysis of Leaf Gas Exchange Data

Description

An implementation of the A-Ci curve for C4 plants, based on von Caemmerer et al. (2000)

Usage

AciC4(
  Ci,
  PPFD = 1500,
  Tleaf = 25,
  VPMAX25 = 120,
  JMAX25 = 400,
  Vcmax = 60,
  Vpr = 80,
  alpha = 0,
  gbs = 0.003,
  O2 = 210,
  x = 0.4,
  THETA = 0.7,
  Q10 = 2.3,
  RD0 = 1,
  RTEMP = 25,
  TBELOW = 0,
  DAYRESP = 1,
  Q10F = 2,
  FRM = 0.5,
  ...
)

Arguments

Ci	Intercellular CO2 concentration (ppm)
PPFD	Photosynthetic photon flux density (mu mol m-2 s-1)
Tleaf	Leaf temperature (C)
VPMAX25	The maximum rate of PEP carboxylation (mu mol m-2 s-1)
JMAX25	Maximum electron transport rate (at 25C)
Vcmax	Maximum rate of carboxylation (mu mol m-2 s-1) (at 25C)
Vpr	PEP regeneration (mu mol m-2 s-1)
alpha	Fraction of PSII activity in the bundle sheath (-)
gbs	Bundle sheath conductance (mol m-2 s-1)
O2	Mesophyll O2 concentration
x	Partitioning factor for electron transport
THETA	Shape parameter of the non-rectangular hyperbola
Q10	T-dependence parameter for Michaelis-Menten coefficients.
RD0	Respiration at base temperature (RTEMP) (mu mol m-2 s-1)
RTEMP	Base leaf temperature for respiration (C)
TBELOW	Below this T, respiration is zero.
DAYRESP	Fraction respiration in the light vs. that measured in the dark
Q10F	T-dependence parameter of respiration
FRM	Fraction of day respiration that is mesophyll respiration (Rm)
...	Further arguments (currently ignored).

Details

Note that the temperature response parameters have been hardwired in this function, and are based on von Caemmerer (2000).

Note that it is not (yet) possible to fit this curve to observations of photosynthesis (see fitaci to fit the C3 model of photosynthesis).

Author(s)

Rhys Whitley

References

Caemmerer, S.V., 2000. Biochemical Models of Leaf Photosynthesis. Csiro Publishing.

Examples

# Simulate a C4 A-Ci curve. 
aci <- AciC4(Ci=seq(5,600, length=101))
with(aci, plot(Ci, ALEAF, type='l', ylim=c(0,max(ALEAF))))

Example output

plantecophys documentation built on April 1, 2021, 1:06 a.m.