Table I.
Physiological properties (mean ± sd) of the intact control cabbages in experiments 1 and 2, and P. xylostella-damaged cabbages in experiment 2
| N | Rinda
|
Lennox
|
|||||
|---|---|---|---|---|---|---|---|
| Ambient CO2 | Elevated CO2 | P | Ambient CO2 | Elevated CO2 | P | ||
| Experiment 1 | |||||||
| Control | |||||||
| SLA (cm2 g dw−1) | 6 | 227.1 ± 40.0 | 190.5 ± 31.7 | 0.110 | 139.5 ± 14.8 | 110.2 ± 9.0 | 0.002 |
| Leaf thickness (μm) | 12 | 293.8 ± 40.9 | 293.1 ± 47.9 | 0.967 | 307 ± 33.8 | 350 ± 41.0 | 0.012 |
| Stomatal density (n mm−2) | |||||||
| 3rd youngest leaf | |||||||
| Adaxial | 6 | 146.0 ± 24.1 | 128.2 ± 16.7 | 0.153 | 207.7 ± 51.2 | 239.1 ± 103.0 | 0.518 |
| Abaxial | 6 | 203.2 ± 26.8 | 202.0 ± 36.9 | 0.950 | 254.4 ± 60.1 | 246.4 ± 21.6 | 0.775 |
| 5th youngest leaf | |||||||
| Adaxia | 6 | 232.0 ± 20.7 | 213.2 ± 42.0 | 0.347 | 288.2 ± 25.4 | 291.4 ± 33.4 | 0.860 |
| Abaxial | 6 | 318.9 ± 32.2 | 286.8 ± 77.1 | 0.370 | 345.8 ± 91.3 | 326.3 ± 57.4 | 0.667 |
| Experiment 2 | |||||||
| Control | |||||||
| Leaf area (cm2) | 5 | 272.7 ± 70.0 | 269.8 ± 27.8 | 0.934 | 218.9 ± 24.3 | 228.8 ± 13.9 | 0.451 |
| SLA (cm2 g dw−1) | 5 | 199.1 ± 49.3 | 143.3 ± 24.6 | 0.053 | 168.5 ± 33.8 | 149.8 ± 30.0 | 0.381 |
| Shoot fresh weight (g) | 5 | 15.8 ± 4.9 | 16.8 ± 2.4 | 0.707 | 12.9 ± 1.4 | 14.2 ± 1.3 | 0.163 |
| Shoot dry weight (g) | 5 | 1.7 ± 0.6 | 2.2 ± 0.4 | 0.136 | 2.0 ± 1.1 | 1.8 ± 0.3 | 0.710 |
| Fresh/dry weight ratio | 5 | 9.6 ± 1.4 | 7.6 ± 1.0 | 0.028 | 7.3 ± 2.7 | 7.8 ± 0.9 | 0.717 |
| P. xylostella | |||||||
| Leaf area (cm2) | 5 | 254.8 ± 27.9 | 227.94 ± 29.2 | 0.174 | 189.0 ± 30.6 | 200.0 ± 5.1 | 0.469 |
| SLA (cm2 g−1) | 5 | 172.5 ± 30.4 | 158.2 ± 28.5 | 0.466 | 158.2 ± 34.6 | 105.0 ± 7.0 | 0.025 |
| Shoot fresh weight (g) | 5 | 15.4 ± 2.4 | 14.23 ± 2.5 | 0.470 | 10.8 ± 2.1 | 12.8 ± 0.6 | 0.100 |
| Shoot dry weight (g) | 5 | 1.8 ± 0.4 | 1.78 ± 0.4 | 0.962 | 1.5 ± 0.5 | 2.2 ± 0.2 | 0.026 |
| Fresh/dry weight ratio | 5 | 8.7 ± 1.1 | 8.17 ± 1.1 | 0.458 | 7.4 ± 1.2 | 5.8 ± 0.3 | 0.037 |
| ∅ < 2 mm holes per leaf | 5 | 2.1 ± 1.6 | 2.6 ± 3.3 | 0.777 | 0.8 ± 0.4 | 1.6 ± 0.5 | 0.020 |
| ∅ > 2 mm holes per leaf | 5 | 7.3 ± 4.2 | 5.7 ± 2.4 | 0.496 | 3.1 ± 1.1 | 5.3 ± 1.0 | 0.009 |
Plants were grown at ambient (360 μmol mol−1) or elevated CO2 (720 μmol mol−1) concentration. The CO2 effect was tested with independent samples t test.