Table 1. Photosynthetic parameters of the D1-R238E tobacco mutant.
| Parameter | Units | WT | WT-aadA | R238E |
|---|---|---|---|---|
| O2 evolution rate* | (μmol O2/(mg Chl ·h)) | 123±6 | 122±8 | 118±6 |
| Leaf absorbance | (%) | 87.6±0.8 | 87.8±1.2 | 87.0±1.3 |
| Fv/Fm | N/A | 0.8 | 0.8 | 0.8 |
| ETR § | (μmol e-/m2/s) | 133±11 | 131±10 | 117±6 |
| Chl content § | (mg/m2) | 535±20 | 531±61 | 501±59 |
| Chla/Chlb ratio | 4.0±0.1 | 4.0±0.1 | 3.9±0.1 | |
| PSI content § | (μmol/m2) | 1.3±0.1 | 1.3±0.2 | 1.2±0.1 |
| b6f complex § | (μmol/m2) | 0.6±0.1 | 0.6±0.1 | 0.5±0.1 |
| PSII content § | (μmol/m2) | 1.3±0.1 | 1.5±0.3 | 1.3±0.2 |
Thylakoids of mutated tobacco lines in which arginine 238 of the D1 protein was modified to glutamate (R238E) display similar photosynthetic characteristics to thylakoids of WT and WT-aadA tobacco lines.
*O2 evolution was determined with a Clark type electrode, with DCBQ as the exogenous electron acceptor.
§The maximum light-saturated linear electron transport capability (ETR), chlorophyll (Chl) content and a/b ratio and the content of major photosynthetic complexes photosystem I (PSI), photosystem II (PSII), and the cytochrome b6f were determined spectroscopically, as detailed in the Experimental section. Values are average of six independent experiments, and presented ± standard error.