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

`J(pars, unitless = FALSE)`

- 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.

Value in \(\mu\)mol/ (m^2 s) of class `units`

\(J\) 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) | \(\mu\)mol 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 | \(\mu\)mol quanta / (m^2 s) | 1500 |

\(\theta_J\) | `theta_J` | curvature factor for light-response curve | none | 0.825 |

```
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)
#> 181.6577 [umol/m^2/s]
```