Table 3.
The physiological parameters (±SE) of the C-specific light–response curves for the gross and net photosynthetic O2 evolution of T. erythraeum IMS101 (n=4) measured using the MIMS light source
| Parameters | Units | Low-CO2 | Mid-CO2 | High-CO2 |
|---|---|---|---|---|
| Gross O2 evolution | ||||
| E0C,max | mmol O2 (g C)–1 h–1 | 1.875 (0.118) A | 3.795 (0.175) C | 2.973 (0.158) B |
| Ek | µmol photons m-2 s–1 | 277 (15) | 250 (20) | 281 (15) |
| αgC | µmol O2 (g C)–1 h–1 (µmol photons m-2 s-1)–1 | 6.78 (0.33) A | 15.35 (0.82) C | 10.58 (0.18) B |
| ϕm,g | mol O2 (mol photons)–1 | 0.037 (0.004) | 0.042 (0.004) | 0.045 (0.003) |
| Net photosynthesis | ||||
| PnC,max | mmol O2 (g C)–1 h–1 | 1.131 (0.061) A | 2.534 (0.287) B | 2.312 (0.140) B |
| Ek | µmol photons m–2 s–1 | 300 (41) | 270 (24) | 270 (10) |
| αnC | µmol O2 (g C)–1 h–1 (µmol photons m–2 s–1)–1 | 3.94 (0.46) A | 9.48 (1.02) B | 8.57 (0.35) B |
| RdC | mmol O2 (g C)–1 h–1 | –0.600 (0.078) | –0.644 (0.132) | –0.659 (0.013) |
| ϕm,n | mol O2 (mol photons)–1 | 0.020 (0.002) A | 0.026 (0.003) A | 0.037 (0.002) B |
| Slopes | ||||
| PnC versus E0C | Dimensionless | 0.571 (0.028) A | 0.646 (0.046) A | 0.791 (0.017) B |
| U0C versus E0C | Dimensionless | 0.429 (0.028) B | 0.354 (0.046) A | 0.209 (0.017) A |
| U0C versus PnC | Dimensionless | 0.701 (0.073) B | 0.553 (0.111) B | 0.254 (0.024) A |
Abbreviations: E0C,max, the C-specific maximum gross O2 evolution rate; PnC,max, the C-specific maximum net O2 evolution rate; Ek, the light saturation parameter; αgC and αnC are the C-specific initial slopes of the light–response curve for net and gross photosynthesis; ϕm,g and ϕm,n are the maximum quantum efficiencies of gross and net O2 evolution calculated using the absorption coefficients reported in Supplementary Table S1; RdC, the C-specific dark respiration rate; Slope=the slope of the regression of E0C against PnC, E0C against O2 uptake (U0C), and U0C against PnC. Letters indicate significant differences between CO2 treatments (one-way ANOVA, Tukey post-hoc test; P<0.05); where B is significantly greater than[A, and C is significantly greater than B and A.