Table 4.
The effects of light orientation and dark chilling on whole leaf maximal phosphoenolpyruvate carboxylase (PEPC) carboxylation rates (Vpmax), maximal ribulose-1,5-bisphosphate (Rubisco) carboxylation rates (Vcmax) and maximal electron transport rates (Jmax). Plants were either maintained at optimal growth temperatures (controls) or subjected to dark chilling for either one or two consecutive nights
Data represent the mean values ± SE of nine plants per treatment and were calculated following the application of the C4 photosynthetic model of von Caemmerer (2000) to the whole leaf CO2-response curves (See Fig. 3). Statistical analysis was performed separately for each parameter. The different letters represent statistical differences at P<0.05.
| Vpmax(μmol m-2 s-1) | Vcmax(μmol m-2 s-1) | Jmax(μmol m-2 s-1) | |
| Light Adaxial | |||
| Control | 111 ± 4.3 a | 32 ± 1.0 a | 214 ± 15.6 a |
| 1 Night Chilling | 52 ± 1.4 c | 22 ± 0.7 c | 144 ± 11.3 b |
| 2 Nights Chilling | 63 ± 1.0 b,c | 28 ± 1.1 a,b | 183 ± 10.2 a,b |
| Light Abaxial | |||
| Control | 58 ± 2.9 b,c | 26 ± 0.5 b | 167 ± 1.6 b |
| 1 Night Chilling | 67 ± 4.8 b | 24 ± 0.8 b,c | 152 ± 6.4 b,c |
| 2 Nights Chilling | 66 ± 2.5 b,c | 22 ± 1.1 c | 148 ± 3.5 c |