Table II.
Sensitivity of leaf level calculations of φ to different values of mitochondrial respiration rate (Rd), fractionation factor associated with mitochondrial respiration (e), and carboxylation rate in BS cells (Vc)
The extended model by Farquhar (1983) was used to calculate the mean absolute difference of φ between the extended model and the simplified version without respiratory fractionation (Eq. 3). Phosphoenolpyruvate carboxylation and photorespiration rates were set at 1.5 and 0.03 times Vc, respectively. A value of 11.5‰ was used for the fractionation factor associated with photorespiration, based on recent estimates by Lanigan et al. (2008).
| Rd | e | Vc | Mean Difference in φ |
|---|---|---|---|
| μmol m−2 s−1 | ‰ | μmol m−2 s−1 | |
| 0.4 | 6 | 30 | 0.0080 |
| 0.4 | −6 | 30 | 0.0032 |
| 0.4 | 6 | 3 | 0.0306 |
| 0.4 | −6 | 3 | −0.018 |
| 1.2 | 6 | 30 | 0.0129 |
| 1.2 | −6 | 30 | −0.0016 |
| 1.2 | 6 | 3 | 0.0852 |
| 1.2 | −6 | 3 | −0.0614 |