Stomatal parameters | CO2 concentration (ppm) | |||||||
---|---|---|---|---|---|---|---|---|
400 | 600 | 800 | 1000 | 1200 | 1400 | 1600 | p value | |
Adaxial surface | ||||||||
Stomatal length (μm) | 9.4 ± 1.3 (a) | 9. 7 ± 1.6 (a) | 9.6 ± 0.6 (a) | 9.6 ± 0.8 (a) | 9.0 ± 2.0 (a) | 9.50 ± 0.5 (a) | 9.8 ± 1.6 (a) | p > 0.05 |
Stomatal width (μm) | 2.2 ± 0.9 (a) | 1.8 ± 0.4 (a) | 2.6 ± 0.5 (a) | 1.7 ± 0.2 (a) | 2.7 ± 0.5 (a) | 2.4 ± 0.5 (a) | 2.5 ± 0.7 (a) | p > 0.05 |
Stomatal area (μm2) | 92.6 ± 16.2 (b) | 88.7 ± 9.6 (b) | 105.4 ± 5.2 (ab) | 83.3 ± 9.0 (b) | 126.4 ± 24.1 (a) | 100.3 ± 17.2 (b) | 103.9 ± 11.0 (ab) | p = 0.03 |
Stomatal perimeter (μm) | 40.7 ± 0.5 (ab) | 45.0 ± 1.0 (ab) | 41.0 ± 0.1 (ab) | 37.9 ± 0.2 (b) | 46.2 ± 0.4 (a) | 40.5 ± 0.3 (ab) | 41.2 ± 0.27 (ab) | p > 0.05 |
Stomatal density (No./mm2) | 16.8 ± 8.9 (a) | 7.3 ± 4.9 (c) | 6.6 ± 4.7 (bc) | 17.8 ± 5.3 (a) | 10.4 ± 6.4 (bc) | 11.4 ± 6.3 (b) | 8.7 ± 3.5 (b) | p = 0.04 |
Stomatal shape index (%) | 24.0 ± 1.3 (a) | 20.4 ± 4.7 (b) | 25.0 ± 0.2 (a) | 24.1 ± 0.2 (a) | 24.3 ± 2.4 (a) | 24.6 ± 0.6 (a) | 24.7 ± 0.7 (a) | p > 0.05 |
Stomatal area index (%) | 9.4 ± 1.7 (a) | 3.9 ± 0.4 (d) | 4.2 ± 0.3 (d) | 9.0 ± 1.0 (a) | 7.9 ± 1.5 (ab | 6.9 ± 1.2 (bc) | 5.4 ± 0.6 (cd) | p < 0.001 |
Abaxial surface | ||||||||
Stomatal length (μm) | 9.6 ± 1.7 (ab) | 9.8 ± 0.6 (ab) | 9.5 ± 0.8 (ab) | 10.2 ± 0.7 (a) | 8.9 ± 0.6 (b) | 9.4 ± 0.2 (ab) | 9.2 ± 0.1 (ab) | p > 0.05 |
Stomatal width (μm) | 3.1 ± 0.9 (a) | 3.1 ± 0.3 (a) | 3.2 ± 0.3 (a) | 2.9 ± 0.4 (a) | 3.0 ± 0.4 (a) | 3.1 ± 0.2 (a) | 2.8 ± 0.1 (a) | p > 0.05 |
Stomatal area (μm2) | 133.1 ± 0.5 (a) | 123.9 ± 16.5 (ab) | 108.9 ± 13.8 (bc) | 102.3 ± 6.1 (c) | 109.3 ± 7.5 (bc) | 113.9 ± 9.2 (abc) | 110.1 ± 17.8 (bc) | p > 0.05 |
Stomatal perimeter (μm) | 42.8 ± 5.5 (a) | 44.6 ± 2.8 (a) | 41.1 ± 3.1 (a) | 40.7 ± 1.4 (a) | 40.7 ± 2.0 (a) | 42.6 ± 1.7 (a) | 41.8 ± 3.3 (a) | p > 0.05 |
Stomatal density (No./mm2) | 101.3 ± 20.1 (abc) | 128.3 ± 18 (a) | 95.7 ± 10.8 (bc) | 92 ± 17.0 (c) | 104.8 ± 9.7 (abc) | 84.2 ± 9.2 (c) | 111.4 ± 17.8 (ab) | p > 0.05 |
Stomatal shape index (%) | 25.3 ± 0.1 (a) | 24.9 ± 0.1 (a) | 25.2 ± 0.4 (a) | 24.9 ± 0.1 (a) | 25.1 ± 0.5 (a) | 25.0 ± 0.4 (a) | 25.1 ± 0. (a) | p > 0.05 |
Stomatal area index (%) | 81.9 ± 0.3 (b) | 96.3 ± 12.8 (a) | 63.2 ± 8.0 (cd) | 57.1 ± 3.4 (d) | 69.5 ± 4.8 (bcd)) | 58.2 ± 4.72 (d) | 74.8 ± 12.1 (bc) | p < 0.001 |
Adaxial/abaxial ratio | 0.23 ± 0.023 (ab) | 0.12 ± 0.022 (c) | 0.13 ± 0.042 (c) | 0.26 ± 0.002(a) | 0.21 ± 0.018 (b) | 0.20 ± 0.013 (b) | 0.09 ± 0.024 (c) | p < 0.001 |