Net Photosynthesis (A, μmol m−2 s−1), Transpiration (E, mmol m−2 s−1) and Stomatal Conductance (gs, mmol m−2 s−1) in different cultivars of Acer platanoides, grown with or without irrigation. Data are reported as means of the values obtained from June to September (five sampling dates in 2006, five in 2007), and subjected to analysis of variance.
| Treatment | A (μmol m−2 s−1) | E (mmol m−2 s−1) | Gs (mmol m−2 s−1) | |||
|---|---|---|---|---|---|---|
| 2006 | 2007 | 2006 | 2007 | 2006 | 2007 | |
| ‘Summershade’ | ||||||
| Irrigated | 6.6 | 8.9 | 2.6 | 3.1 | 118.2 | 175.2 |
| Nonirrigated | 6.1 | 7.8 | 1.9 | 2.5 | 93.0 | 148.9 |
| P | N.S. | N.S. | ** | ** | ** | N.S. |
| ‘Deborah’ | ||||||
| Irrigated | 9.5 | 9.0 | 3.2 | 3.1 | 163.4 | 179.0 |
| Nonirrigated | 8.4 | 8.6 | 2.7 | 3.2 | 147.0 | 194.3 |
| P | ** | N.S. | ** | N.S. | ** | N.S. |
| ‘Emerald Queen’ | ||||||
| Irrigated | 7.8 | 8.9 | 2.6 | 3.0 | 124.7 | 174.5 |
| Nonirrigated | 7.5 | 8.1 | 2.4 | 2.7 | 117.5 | 124.7 |
| P | N.S. | N.S. | N.S. | * | N.S. | N.S. |
* and ** indicate statistical differences at P < 0.05 (*) or P < 0.01 (**) between irrigated and nonirrigated plants of the same cultivar.