Table I.
Symbols used in text
| A | Net photosynthesis rate |
| ā | Weighted mean discrimination against C18OO for diffusion from chloroplast to atmosphere |
| a | Discrimination against C18OO during diffusion through stomata |
| ab | Discrimination against C18OO during diffusion through leaf boundary layer |
| aw | Summed discriminations against C18OO during liquid phase diffusion and dissolution |
| a13 | Discrimination against 13CO2 during diffusion through stomata |
| ab13 | Discrimination against 13CO2 during diffusion through leaf boundary layer |
| aw13 | Summed discrimination against 13CO2 during dissolution and liquid phase diffusion |
| αw | Equilibrium oxygen isotope effect between CO2 and water |
| b | Discrimination against 13CO2 by carboxylating enzymes |
| b18 | Discrimination against C18OO by Rubisco |
| C | Molar concentration of water |
| Ca | Partial pressure of CO2 in atmosphere |
| Cc | Partial pressure of CO2 in chloroplast |
| Ccs | Partial pressure of CO2 at the chloroplast surface |
| Ci | Partial pressure of CO2 in leaf intercellular air spaces |
| Cin | Partial pressure of CO2 in dry air entering leaf chamber |
| Cs | Partial pressure of CO2 at the leaf surface |
| ci | Mole fraction of CO2 in intercellular air spaces |
| ca | Mole fraction of CO2 in atmosphere |
| D | Diffusivity of H218O in water |
| ΔA | Discrimination against 13C or 18O during net CO2 uptake by photosynthesis |
| Δca | 18O enrichment of CO2 in chloroplast compared to atmosphere |
| Δe | 18O enrichment at evaporative sites in leaves compared to source water |
| Δea | 18O enrichment of CO2 in chloroplast compared to atmosphere when chloroplast CO2 is in full equilibrium with chloroplast water |
| Δi | Discrimination against 13CO2 that would occur if gi were infinite and photorespiration and day respiration did not discriminate |
| ΔL | 18O enrichment of average lamina leaf water compared to source water |
| Δobs | Observed discrimination against 13CO2 during photosynthesis |
| Δv | 18O enrichment of vapor in atmosphere compared to source water |
| δA | δ18O of CO2 taken up by net photosynthesis (VSMOW scale) |
| δa | δ18O of CO2 in atmosphere (VSMOW scale) |
| δc | δ18O of CO2 in chloroplast (VSMOW scale) |
| δc0 | δ18O of CO2 in chloroplast that has not equilibrated with chloroplast water (VSMOW scale) |
| δe | δ18O of water at evaporative sites in leaves (VSMOW scale) |
| δin | δ18O of CO2 in air entering leaf chamber (VSMOW scale) |
| δL | δ18O of average lamina leaf water (VSMOW scale) |
| δR | δ18O of CO2 efflux during dark respiration (VSMOW scale) |
| δs | δ18O of source water (VSMOW scale) |
| E | Transpiration rate |
| e | Discrimination against 13C during day respiration |
| ea | Vapor pressure in atmosphere |
| ei | Vapor pressure in leaf intercellular air spaces |
| ɛ+ | Equilibrium 18O fractionation between liquid water and vapor |
| ɛk | Kinetic fractionation during diffusion of H218O from leaf intercellular air spaces to atmosphere |
| ɛw | Equilibrium 18O fractionation between CO2 and water |
| f | Discrimination against 13C during photorespiration |
| gt | Conductance to H2O from leaf intercellular air space to atmosphere |
| gi | Conductance to CO2 from leaf intercellular air spaces to sites of carboxylation |
| gtc | Conductance to CO2 from chloroplast to atmosphere |
| Γ* | CO2 compensation point in absence of day respiration |
| k | Carboxylation efficiency |
| L | Scaled effective path length for calculation of ℘ |
| Λ | Area of leaf in leaf chamber |
| m13 | Slope of the relationship between Δi − Δobs and A/Ca |
| m | Slope of the relationship between δc and δe |
| n | Number of measurements in each experiment |
| ℘ | Péclet number |
| θ | Propotion of chloroplast CO2 isotopically equilibrated with chloroplast water |
| P | Atmospheric pressure |
| RA | 13C/12C or 18O/16O of net CO2 uptake by photosynthesis |
| Ra | 13C/12C or 18O/16O of CO2 in atmosphere |
| Rce | 18O/16O of CO2 in equilibrium with chloroplast water |
| Rc0 | 18O/16O of chloroplast CO2 that has not equilibrated with chloroplast water |
| Re | 18O/16O of water at evaporative sites in leaves |
| RR | 18O/16O of net CO2 efflux during dark respiration |
| RStd | 18O/16O of VSMOW standard |
| rs | Stomatal resistance to water vapor diffusion |
| rb | Leaf boundary layer resistance to water vapor diffusion |
| ℜd | Day respiration rate |
| ℜn | Net CO2 efflux rate during dark respiration |
| ρ | Ratio of rates of carboxylation and CO2 hydration in chloroplast |
| Tleaf | Leaf temperature |
| u | Flow rate of air through leaf chamber |
| wi | Mole fraction of water vapor in the leaf intercellular air spaces |
| W | Leaf lamina water concentration |