A |
Net CO2 assimilation |
a |
Fractionation during diffusion of CO2 from the chloroplast to the atmosphere (4.4‰) |
al
|
Fractionation of CO2 diffusion through a liquid (0.7‰) |
BSC |
Bundle sheath cells |
b3
|
Combined discrimination of Rubisco, respiration, and photorespiration (see Eq. 4) |
b4
|
Combined discrimination of PEPC, respiration, and hydration/dehydration of CO2 (see Eq. 3 and Fig. 4) |
bp
|
Discrimination by PEPC (2.2‰) |
Δ13C |
Carbon isotope discrimination |
CA |
Carbon anhydrase |
e |
Fractionation during respiration (3‰ or −6‰) |
es
|
Fractionation as CO2 dissolves (1.1‰) |
eb
|
Equilibrium fractionation factor for the catalyzed hydration/dehydration of CO2 (−9‰) |
f |
Discrimination during photorespiration (10‰ or −6.8‰) |
φ |
The fraction of CO2 fixed by PEPC that subsequently leaks out of the BSC |
gw
|
The internal conductance to the diffusion of CO2 between the intercellular air space and the site of carboxylation in the mesophyll cytoplasm |
h |
Catalyzed fractionation during CO2 hydration (1.1‰) |
kCA
|
Rate constant of carbonic anhydrase |
Kc
|
Michaelis constant of Rubisco for CO2
|
Ko
|
Michaelis constant of Rubisco for O2
|
Kp
|
Michaelis constant of PEPC for CO2
|
Md
|
Rate of mitochondrial respiration |
Mm
|
Rate of mitochondrial respiration in the mesophyll cells |
Ms
|
Rate of mitochondrial respiration in the BSC |
pCO2
|
Partial pressure of CO2
|
pe
|
pCO2 of dry air entering the leaf chamber |
pi
|
pCO2 of the intercellular airspace |
pm
|
pCO2 of the mesophyll cytoplasm |
po
|
pCO2 of dry air leaving the leaf chamber |
Re
|
13C/12C of the air entering the leaf chamber |
Ro
|
13C/12C of the air leaving the leaf chamber |
PFD |
Photon flux density |
PSII |
PSII |
ξ |
pe/(pe − po) |
s |
Fractionation during the leakage of CO2 from the BSC (1.8‰) |
Vc
|
Rate of Rubisco carboxylation |
Vcmax
|
Maximal rate of Rubisco carboxylation |
Vh
|
Rate of CO2 hydration |
Vo
|
Rate of photorespiration |
Vp
|
Rate of PEP carboxylation (A + Md)/(1 − φ) or (pmVpmax)/(pm + Kp) |
Vpmax
|
Maximal rate of PEPC carboxylation |