Table 1.
Glossary of terms
| Term | Definition |
|---|---|
| Δ13C | Photosynthetic carbon discrimination (δ13Cambient−δ13CBL) |
| δ13CBL | Leaf carbon isotopic composition |
| δ18OLW | Oxygen isotopic composition of leaf water |
| δ18OSW | Oxygen isotopic composition of soil water |
| δ18ORC | Oxygen isotopic composition of root crown water |
| δ18OS | Oxygen isotopic composition of source water |
| δ18OI | Oxygen isotopic composition of irrigation water |
| Δ18OLW | Leaf water enrichment (δ18OLW−δ18OS) |
| Δ18OBL | Bulk leaf enrichment (δ18OBL−δ18OS) |
| Δ18Ov | Enrichment of water vapor above source water (δ18Ov−δ18OS) |
| C i/Ca | Intercellular to ambient CO2 concentration |
| g s | Stomatal conductance (mol m−2 s−1) |
| A net | Net photosynthetic rate (µmol m−2 s−1) |
| E | Transpiration rate (mmol m−2 s−1) |
| TEintrinsic | Intrinsic transpiration efficiency (Anet/gs) |
| TEinstantaneous | Instantaneous transpiration efficiency (Anet/E) |
| TEplant | Plant level transpiration efficiency (total aboveground biomass/water transpired) |
| TEw | δ13CBL-derived transpiration efficiency |
| e a/ei | Molar ratio of ambient to intercellular vapor |
| ε+ | Equilibrium fractionation |
| εk | Kinetic fractionation |
| ϕw | Ratio of night-time and non-stomatal water loss to daytime transpiration |
| ϕr | Ratio of CO2 respiration occurring at night and in non- photosynthetic tissue during the day to assimilation rate |
| A | Fractionation during diffusion of CO2 in air through stomata (4.4‰) |
| b 3 | Fractionation by Rubisco (30‰) |
| b 4 | Fractionation of PEP carboxylation and isotopic equilibrium during dissolution and hydration of CO2 (–5.2‰ at a leaf temperature of 30 °C) |
| S | Fractionation during the CO2 leakage from the bundle sheath cells (1.8‰) |
| ϕ | Leakiness of CO2 from the bundle sheath |