Arrhenius.temp.response {bigleaf}

(Modified) Arrhenius Temperature Response Function

Description

(Modified) Arrhenius function describing the temperature response of biochemical parameters.

Usage

Arrhenius.temp.response(
  param,
  Temp,
  Ha,
  Hd,
  dS,
  constants = bigleaf.constants()
)

Arguments

param

Parameter measured at measurement temperature (umol m-2 s-1)

Temp

Measurement temperature (degC)

Ha

Activation energy for param (kJ mol-1)

Hd

Deactivation energy for param (kJ mol-1)

dS

Entropy term for param (kJ mol-1 K-1)

constants

Kelvin - conversion degree Celsius to Kelvin
Rgas - universal gas constant (J mol-1 K-1)
kJ2J - conversion kilojoule (kJ) to joule (J)

Details

The function returns the biochemical rate at a reference temperature of 25degC given a predefined temperature response function. This temperature response is given by a modified form of the Arrhenius function:

param25 = param / ( exp(Ha * (Temp - Tref) / (Tref*Rgas*Temp)) * (1 + exp((Tref*dS - Hd) / (Tref * Rgas))) / (1 + exp((Temp*dS - Hd) / (Temp * Rgas))) )

where param is the value/rate of the parameter at measurement temperature, Temp is temperature in K, Tref is reference temperature (298.15K), and Rgas is the universal gas constant (8.314 J K-1 mol-1). Ha is the activation energy (kJ mol-1), Hd is the deactivation energy (kJ mol-1), and dS the entropy term (kJ mol-1 K-1) of the respective parameter.

If either Hd or dS or both are not provided, the equation above reduces to the first term (i.e. the common Arrhenius equation without the deactivation term.)

Value

param25 - value of the input parameter at the reference temperature of 25degC (umol m-2 s-1)

References

Johnson F.H., Eyring H., Williams R.W. 1942: The nature of enzyme inhibitions in bacterial luminescence: sulfanilamide, urethane, temperature and pressure. Journal of cellular and comparative physiology 20, 247-268.

Kattge J., Knorr W., 2007: Temperature acclimation in a biochemical model of photosynthesis: a reanalysis of data from 36 species. Plant, Cell and Environment 30, 1176-1190.