Percent increase (+) in leaf chlorophyll content (SPAD values) after 72 hours following heat stress (44 °C, 20 minutes) in foliar tissue of 8 Acer species. Species are ranked in order of tolerance based on percent increases in leaf chlorophyll content (SPAD values) as a measure of recovery from damage to the leaf chloroplast membrane.
| Species | SPAD |
|---|---|
| A. platanoides ‘Drummondii’ | +22.8a |
| A. platanoides ‘Princeton Gold’ | +17.9a |
| A. platanoides ‘Emerald Queen’ | +11.7a |
| A. platanoides ‘Royal Red’ | +9.80a |
| A. campestre ‘Louisa Red Shine’ | +7.26a |
| A. campestre | +4.92a |
| A. pseudoplatanus ‘Negenia’ | +2.86a |
| A. pseudoplatanus ‘Spaethii’ | +2.28a |
Numbers within a column followed by a common letter (taken from regression equations [Figure 4]) are not significantly different according to Tukey’s honest significance test (P = 0.05).