Effect of temperature, Ci, and O2 on Pn and Rubisco activation in intact creosote bush leaves
| Temperature | O2 | Ci | Pn | Rubisco activation |
|---|---|---|---|---|
| °C | mbar | μbar | μmol m−2 s−1 | % |
| 28 | 210 | 261 | 29.0 ± 0.6 | 100 |
| 28 | 10 | 243 | 43.9 ± 1.1 | 79.4 |
| 40 | 210 | 258 | 23.3 ± 1.6 | 84.7 |
| 42.5 | 210 | 262 | 19.3 ± 1.6 | 60 |
| 42.5 | 10 | 241 | 32.8 ± 1.1 | NDa |
| 42.5 | 10 | 335 | 39.8 ± 1.4 | ND |
| 42.5 | 10 | 489 | 49.5 ± 0.7 | ND |
| 42.5 | 10 | 687 | 56.4 ± 0.7 | ND |
| 42.5 | 10 | 844 | 59.0 ± 0.3 | 39.1 |
The Pn of each of three sets of leaves was measured under all of the conditions listed below by continuously changing the O2, temperature, and Ci after first achieving a steady-state rate at 28°C, 210 mbar O2, and 261 μbar Ci. Rubisco activation was measured by rapid extraction and assay of freeze-clamped leaves. By necessity, separate sets of leaves were used for determining Rubisco activation.
↵a ND, Not determined.