J {photosynthesis}

J: Rate of electron transport (umol/m^2/s)

Description

Calculate the rate of electron transport as a function of photosynthetic photon flux density (PPFD).

Usage

J(pars, unitless = FALSE)

Arguments

pars

Concatenated parameters (leaf_par, enviro_par, and constants)

unitless

Logical. Should units be set? The function is faster when FALSE, but input must be in correct units or else results will be incorrect without any warning.

Details

J as a function of PPFD is the solution to the quadratic expression:

0 = \theta_J J ^ 2 - J (J_\mathrm{max} + \phi_J PPFD) + J_\mathrm{max} \phi_J PPFD

Symbol	R	Description	Units	Default
J_\mathrm{max}	J_max	potential electron transport (T_leaf)	\mumol CO2 / (m^2 s)	calculated
\phi_J	phi_J	initial slope of the response of J to PPFD	none	0.331
PPFD	PPFD	photosynthetic photon flux density	\mumol quanta / (m^2 s)	1500
\theta_J	theta_J	curvature factor for light-response curve	none	0.825

Value

Value in \mumol/ (m^2 s) of class units

Examples

library(magrittr)
library(photosynthesis)

bake_par = make_bakepar()
constants = make_constants(use_tealeaves = FALSE)
enviro_par = make_enviropar(use_tealeaves = FALSE)
leaf_par = make_leafpar(use_tealeaves = FALSE)
enviro_par$T_air = leaf_par$T_leaf
leaf_par %<>% bake(enviro_par, bake_par, constants)

pars = c(leaf_par, enviro_par, constants)
J(pars, FALSE)