Percent reduction (–) in Fv/Fm compared to zero values (i.e., before heat stress was imposed). Species are ranked in order of tolerance based on percent reductions in Fv/Fm as a measure of damage to the leaf photosynthetic system.
| Fv/Fm | ||
|---|---|---|
| Species | July | August |
| A. pseudoplatanus ‘Negenia’ | –18.2d | –7.3c |
| A. pseudoplatanus ‘Spaethii’ | –29.0c | –11.4c |
| A. platanoides ‘Royal Red’ | –33.6bc | –12.8c |
| A. campestre | –31.6bc | –13.9c |
| A. campestre ‘Louisa Red Shine’ | –34.4bc | –31.6b |
| A. platanoides ‘Princeton Gold’ | –36.0bc | –26.4b |
| A. platanoides ‘Emerald Queen’ | –40.8b | –32.0b |
| A. platanoides ‘Drummondii’ | –53.0a | –47.9a |
Numbers within a column followed by a common letter (taken from regression equations [Figure 1]) are not significantly different according to Tukey’s honest significance test (P = 0.05).