Leaf parameter temperature responses
'bake' leaf parameters using temperature response functions
Constructor function for baked class. This will also inherit class
leaf_par. This function ensures that temperature is "baked in"
to leaf parameter calculations T_leaf using temperature response
functions detailed below.
bake(leaf_par, bake_par, constants, assert_units = TRUE) temp_resp1(par25, E_a, R, T_leaf, T_ref, unitless) temp_resp2(par25, D_s, E_a, E_d, R, T_leaf, T_ref, unitless)
leaf_par |
A list of leaf parameters inheriting class |
bake_par |
A list of temperature response parameters inheriting class |
constants |
A list of physical constants inheriting class |
assert_units |
Logical. Should parameter |
par25 |
Parameter value at 25 °C of class |
E_a |
Empirical temperature response value in J/mol of class
|
R |
Ideal gas constant in J / (mol K) of class |
T_leaf |
Leaf temperature in K of class |
T_ref |
Reference temperature in K of class |
unitless |
Logical. Should |
D_s |
Empirical temperature response value in J / (mol K) of class
|
E_d |
Empirical temperature response value in J/mol of class
|
Several leaf parameters (leaf_par) are temperature sensitive.
Temperature-sensitive parameters are input at a reference temperature of
25 °C. These parameters are provided as par_name25 and then "baked"
using the appropriate temperature response function and parameters in
bake_par. The "baked" parameter will have the name without "25"
appended (par_name). E.g. V_cmax25 becomes V_cmax.
Temperature response functions following Bernacchi et al. 2002.
Temperature response function 1 (temp_response1):
par(T_leaf) = par25 exp(E_a / (R T_ref) (T_leaf - 25) / (T_leaf + 273.15))
T_ref is the reference temperature in K
T_leaf is the leaf temperature in °C
Temperature response function 2 (temp_response2) is the above equation multiplied by:
(1 + exp((D_s / R - E_d / (R T_ref)))) / (1 + exp((D_s / R) - (E_d / (R (T_leaf + 273.15)))))
Function 1 increases exponentially with temperature; Function 2 peaks a particular temperature.
Bernacchi CJ, Portis AR, Nakano H, von Caemmerer S, Long SP. 2002. Temperature response of mesophyll conductance. Implications for the determination of Rubisco enzyme kinetics and for limitations to photosynthesis in vivo. Plant Physiology 130: 1992-8.
bake_par <- make_bakepar() constants <- make_constants(use_tealeaves = FALSE) leaf_par <- make_leafpar( replace = list(T_leaf = set_units(293.15, "K")), use_tealeaves = FALSE ) baked_leafpar <- bake(leaf_par, bake_par, constants) baked_leafpar$V_cmax25 baked_leafpar$V_cmax
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