Table 1.
Net photosynthesis rate (Pn), stomatal conductance (gs), transpiration rate (E), and instantaneous water use efficiency (WUE) of immature and mature leaves of wild-type ‘Penncross’ (WT) and SAG12-ipt (S41) plants exposed to PEG-induced drought stress via reduced osmotic potential of the growing solution (–0.7 and –1.0 MPa)
Values followed by the same letter are not significantly different based on Fisher's protected LSD test (P ≤0.05) between plant lines at a given osmotic potential.
| Leaf age | MPa | Plant | Pn | gs | E | WUE |
| (CO2 μmol m−2 s−1) | (mmol) | (mmol H2O m−2 s−1) | (μmol mmol−1) | |||
| Immature | –0.7 | WT | 5.35 b | 13.96 a | 3.31 a | 1.62 b |
| S41 | 5.66 a | 12.62 a | 2.84 a | 1.99 a | ||
| LSD | 0.29 | 0.70 | 1.00 | 0.31 | ||
| –1.0 | WT | 1.41 b | 2.05 a | 0.71 a | 1.98 a | |
| S41 | 1.74 a | 2.93 a | 0.79 a | 2.21 a | ||
| LSD | 0.27 | 1.30 | 0.30 | 0.50 | ||
| Mature | –0.7 | WT | 2.83 b | 6.32 b | 2.26 a | 1.25 b |
| S41 | 3.82 a | 8.52 a | 2.37 a | 1.61 a | ||
| LSD | 0.42 | 0.40 | 0.60 | 0.30 | ||
| –1.0 | WT | 0.29 a | 1.86 a | 0.55 a | 0.52 b | |
| S41 | 0.26 a | 1.97 a | 0.38 a | 0.68 a | ||
| LSD | 0.31 | 0.18 | 0.29 | 0.15 |