Table 2.
Comparison of photosynthesis parameters.
| ᴦ μmol CO2 m−2 s-1 | CE μmol CO2 m−2 s-1 μmol CO2 mol-1 | Rd μmol CO2 m−2 s-1 | Φ | |
|---|---|---|---|---|
| 21 % O2 | ||||
| Wild-type | 51.69 ± 1.59c | 0.126 ± 0.02a | 0.53 ± 0.05a | 0.046 ± 0.03a |
| rbcs2-165 | 51.92 ± 0.15c | 0.067 ± 0.0b | 0.41 ± 0.03b | 0.039 ± 0.02b |
| rbcs2-266 | 66.72 ± 1.45a | 0.046 ± 0.0b | 0.39 ± 0.07b | 0.031 ± 0.00b |
| rbcs4-022 | 57.77 ± 1.58b | 0.05 ± 0.01b | 0.35 ± 0.02b | 0.030 ± 0.00b |
| rbcs4-053 | 49.85 ± 2.71c | 0.06 ± 0.01b | 0.48 ± 0.05b | 0.025 ± 0.00b |
| 2 % O2 | ||||
| Wild-type | 13.32 ± 0.95c | 0.166 ± 0.04a | – | – |
| rbcs2-165 | 14.67 ± 1.11c | 0.086 ± 0.0b | – | – |
| rbcs2-266 | 24.88 ± 1.54a | 0.057 ± 0.0b | – | – |
| rbcs4-022 | 19.54 ± 0.71b | 0.06 ± 0.01b | – | – |
| rbcs4-053 | 14.24 ± 3.12c | 0.08 ± 0.01b | – | – |
CO2 compensation point (ᴦ), carboxylation efficiency (CE), respiration rate (Rd) and quantum efficiency (Φ) of wild type and rbcs2 and rbcs4 antisense lines. Measurements for CE and ᴦ were made at a photosynthetic photon flux density (PPFD) of 2000 μmol photons m–2 s–1, leaf temperature 30 °C and either 21 % or 2% O2. Measurements of Rd were made after 30 min in the dark. Measurements of Φ were made at a CO2 concentration of 400 μmol CO2 mol–1 and a leaf temperature of 30 °C. Values represent the mean ± SE of three leaves from three individual plants. Different letters within groups indicate statistical significance from a one-way ANOVA (p ≤ 0.05) and a least significant difference test (LSD) for post-hoc pairwise comparison.