Table 1.
Functional Organization of the Photosynthetic Apparatus in Wild-Type Tobacco and in Δrpl33 Plants
| Parameter | Wild Type (Mature Leaf)a | Δrpl33 (Mature Leaf)a | Wild Type (Young Expanding Leaf)b | Δrpl33 (Young Expanding Leaf)b |
|---|---|---|---|---|
| Chlorophyll content (mg m−2) | 266.1 ± 14.1 | 250.5 ± 13.9 | 223.5 ± 7.9 | 171.5 ± 12.4 |
| Chlorophyll a/b | 3.80 ± 0.04 | 3.41 ± 0.03 | 3.79 ± 0.11 | 3.35 ± 0.09 |
| Fv/Fmc | 0.81 ± 0.00 | 0.78 ± 0.01 | 0.79 ± 0.01 | 0.65 ± 0.04 |
| Assimilation (μmol CO2 m−2 s−1) | 23.9 ± 1.4 | 20.6 ± 1.0 | – | – |
| PSII [mmoles (mol chlorophyll)−1] | 2.22 ± 0.17 | 2.08 ± 0.08 | – | – |
| Cytochrome bf complex [mmoles (mol chlorophyll)−1] | 1.09 ± 0.04 | 1.02 ± 0.04 | – | – |
| PC/PSId | 3.09 ± 0.14 | 3.65 ± 0.28 | 3.55 ± 0.35 | 4.90 ± 0.90 |
| PSI [mmoles (mol chlorophyll)−1] | 2.26 ± 0.03 | 2.22 ± 0.02 | – | – |
| P700 (leaf) [ΔI/I × 10−3 (mg chlorophyll)−1]e | 47.3 ± 0.1 | 43.0 ± 1.6 | 39.0 ± 1.9 | 33.8 ± 5.1 |
Measurements were performed on mature leaves (length > 10 cm).
Measurements were performed on young expanding leaves (length < 5 cm). Due to the small leaf sizes of expanding leaves, no thylakoids could be isolated, so that exact quantifications of the photosynthetic complexes were only performed on mature leaves.
Fv, variable fluorescence; Fm, maximum fluorescence.
The PC contents relative to P700 were measured in vivo on intact leaves.
The transmission changes (ΔI/I) of P700 measured on intact leaves can be used as an indirect measure of PSI content per chlorophyll, assuming that leaf architecture and, thus, length of the optical path within the leaves is comparable for wild-type and knockout plants.