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Table II
Comparison of mean values of maximum assimilation rate (Amax) and maximum stomatal conductance (gsmax) between CO2 partial pressure treatments for each elevation and species. Na is the leaf nitrogen content. Values in parenthesis correspond to the standard error and n is the number of replicates per population. Differences between treatments were performed using a paired t-test: ns, non-significant differences between PCO2 treatments.
| Amax (μmol m−2 s−1) | gsmax (mmol m−2 s−1) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Species | Elevation (m) | n | Na (mg m−2) | |||||||||
| At ambient | At constant | At ambient | At constant | |||||||||
| PCO2 | PCO2 | PCO2 | PCO2 | |||||||||
| Beech | 131 | 9 | 8.9 (0.72) | 8.8 (0.74) | ns | 131.6 (9.9) | 133.0 (12.6) | ns | 1.22 (0.1) | |||
| 495 | 11 | 8.4 (0.24) | 8.8 (0.44) | ns | 116.4 (6.7) | 115.0 (9.4) | ns | 1.01 (0.07) | ||||
| 773 | 16 | 8.7 (0.75) | 9.9 (0.77) | * | 130.7 (14.4) | 128.5 (15.6) | ns | 1.41 (0.13) | ||||
| 1190 | 10 | 8.8 (0.66) | 11.3 (0.64) | ** | 149.3 (17.4) | 153.0 (16.7) | ns | 1.62 (0.11) | ||||
| 1604 | 15 | 9.5 (0.42) | 12.7 (0.50) | *** | 183.7 (11.1) | 177.7 (8.0) | ns | 2.26 (0.14) | ||||
| Oak | 131 | 19 | 10.0 (0.80) | 9.9 (0.81) | ns | 148.2 (15.2) | 151.5 (14.7) | ns | 1.55 (0.07) | |||
| 425 | 12 | 11.7 (0.66) | 11.9 (0.74) | ns | 173.3 (13.3) | 177.8 (15.3) | ns | 1.87 (0.07) | ||||
| 627 | 11 | 9.6 (0.85) | 10.5 (0.87) | ** | 152.7 (19.8) | 141.3 (15.1) | ns | – | ||||
| 803 | 12 | 12.2 (0.69) | 13.7 (0.74) | * | 91.1 (13.9) | 87.8 (13.0) | ns | 1.82 (0.13) | ||||
| 1235 | 5 | 9.1 (1.30) | 12.8 (0.88) | * | 153.2 (32.2) | 203.8 (21.1) | ns | 1.85 (0.12) | ||||
| 1608 | 10 | 11.9 (0.74) | 14.2 (0.84) | *** | 366.4 (17.0) | 331.5 (17.1) | * | 2.41 (0.07) | ||||