Table 2.
Summary of modelled parameters for temperature response of photosynthesis
| Parameter | Constant | Ambient growth CO2 | Elevated growth CO2 |
|---|---|---|---|
| A sat (µmol m−2 s−1) | T opt (°C) | 23.7±1.1 a | 23.4±1.3 a |
| A opt | 25.5±1.3 a | 30.9±2.7 b | |
| V cmax (µmol m−2 s−1) | V cmax at 25 °C | 149±6 a | 121±12 a |
| E a V (kJ mol−1) | 51±4 a | 38±10 a | |
| J max (µmol m−2 s−1) | J max at 25 °C | 200±12 a | 190±22 a |
| T opt (°C) | 29.5±0.7 a | 27.5±0.9 a | |
| J max at Topt | 233±6 | 210±11 a | |
| E a J (kJ mol−1) | 37±11 a | 34±22 a | |
| ΔSJ (J mol−1 K−1) | 648±5 a | 651±8 a | |
| H d (kJ mol−1) | 200 | ||
| R d (µmol m−2 s−1) | R d at 25 °C | 2.4±0.1 a | 2.2±0.1 a |
| E a R (kJ mol−1) | 41±3 a | 31±6 a | |
| Q 10 | 1.73±0.07 a | 1.50±0.13 a |
Summary of coefficients derived using non-linear least square fitting of CO2 assimilation rates, maximal rate of carboxylation (Vcmax), and maximal rate of RuBP regeneration (Jmax) determined using A–Ci response curves and dark respiration measured at five leaf temperatures (15, 20, 25, 30, and 35 °C). Values are means ±SEs. Derived parameters include temperature optima (Topt) of photosynthesis (Aopt); activation energy for carboxylation (EaV); activation energy (EaJ)¸ entropy term (∆SJ), and Topt and corresponding value for Jmax with deactivation energy (Hd) assumed constant; and activation energy (EaR) and temperature coefficient (Q10) for dark respiration. Letters indicate significance of variation in means (n=6)