Table I.
Symbols used in the text
| Symbol | Description |
|---|---|
| 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 |