Table I.
Zx content and initial rates of electron transport and Vx de-epoxidation
Detached leaves were illuminated at a light intensity of 100 μmol photons m−2 s−1. The Zx content was determined after 1 min of illumination. Relative electron transport rates under in vivo conditions were derived from Chl fluorescence measurements during the first minute of illumination. De-epoxidation rates (expressed as percentage of the sum of Vx + Ax + Zx) were calculated from HPLC analysis of the pigment content in the dark and after 0.5 and 1 min. Mean values ± sd of three to four independent experiments are shown. Significant differences in comparison with respective wild-type values are indicated by ** (P < 0.01) or * (P < 0.05).
| Zx Content | Initial Rate
|
|||
|---|---|---|---|---|
| De-Epoxidation
|
Electron Transport | |||
| 0.5 Ax + Zx | Zx | |||
| mmol (mol Chl)−1 | min−1 | |||
| Wild Type | 1.9 ± 0.6 | 8.7 ± 1.2 | 5.7 ± 1.0 | 13.6 ± 1.6 |
| npq1 | 0 | 0 | 0 | 14.8 ± 2.8 |
| npq2 | 113 ± 9.0 | 0 | 0 | 11.7 ± 1.2 |
| npq4 | 1.5 ± 0.2 | 8.0 ± 1.0 | 5.5 ± 0.8 | 12.8 ± 2.1 |
| pgr1 | **1.0 ± 0.2 | **5.7 ± 1.1 | **3.7 ± 0.5 | *10.3 ± 2.1 |