Temperature dependence of Jmax and Vcmax — f.modified.arrhenius • LeafGasExchange

The temperature dependence of the photosynthetic parameters Vcmax, the maximum catalytic rate of the enzyme Rubisco, and Jmax, the maximum electron transport rate is modeled by a modified Arrhenius equation. It is modified to account for decreases in each parameter at high temperatures.

f.modified.arrhenius(PRef, Ha, Hd, s, Tleaf, TRef = 298.16, R = 8.314)

Arguments

PRef: Value of the parameter, here Vcmax or Jmax, at the reference temperature in micromol.m-2.s-1.
Ha: Energy of activation in J.mol-1.
Hd: Energy of desactivation in J.mol-1.
s: Entropy term in J.mol-1.K-1.
Tleaf: Temperature of the leaf in Kelvin.
TRef: Reference temperature in Kelvin, usually 25 + 273.16 K.
R: Ideal gas constant.

Value

Value of the parameter Jmax or Vcmax at a given temperature

References

Leuning, R. (2002), Temperature dependence of two parameters in a photosynthesis model. Plant, Cell & Environment, 25: 1205-1210. doi:10.1046/j.1365-3040.2002.00898.x.

Examples

plot(x=seq(25,35,0.1),y=f.modified.arrhenius(PRef=50,Ha=73637,Hd=149252,s=486,Tleaf=seq(273.15+25,273.15+35,0.1)),xlab='Temperature degree C',ylab='Vcmax')