Table III.
Gas exchange parameters at saturating light levels (1,600 μmol m−2 s−1) of the sixth leaf of wild-type and ethylene-insensitive tobacco plants
Mean values ± se of the light-saturated rate of photosynthesis (Amax), stomatal conductance (gs), light-saturated rate of photosynthesis per unit chlorophyll (Amax/Chl), carboxylation capacity per unit area (Vcmax), electron transport capacity per unit area (Jmax), and Jmax/Vcmax ratio are shown (n = 8). *, P < 0.05; ***, P < 0.001; ns, not significant.
| Parameter | Wild Type | Ethylene Insensitive | % Difference | P |
|---|---|---|---|---|
| Amax (μmol m−2 s−1) | 17.0 ± 0.7 | 13.3 ± 0.8 | −22 | * |
| gs for CO2 (mmol m−2 s−1) | 233 ± 15 | 275 ± 15 | +18 | * |
| Amax/Chl (mmol mol−1 s−1) | 46 ± 2 | 37 ± 2 | −20 | * |
| Vcmax (μmol CO2 m−2 s−1) | 61 ± 3 | 48 ± 1 | −21 | *** |
| Jmax (μmol e− m−2 s−1) | 115 ± 4 | 98 ± 2 | −15 | *** |
| Jmax/Vcmax (mol e− mol−1 CO2) | 1.88 ± 0.02 | 2.06 ± 0.01 | +10 | *** |