Table II.
Effect of UV-B irradiation (0.63 W m−2) on gs
| Species | Leaf Position | Control | UV-B | Percentage Reduction | P |
|---|---|---|---|---|---|
| mol m−2 s−1 | |||||
| C. communis (n = 5) | Adaxial | 0.09 ± 0.02 | 0.06 ± 0.01 | 39 | 0.099 |
| Abaxial | 0.33 ± 0.04 | 0.27 ± 0.03 | 17 | NS | |
| Total | 0.43 ± 0.05 | 0.33 ± 0.03 | 22 | 0.041 | |
| B. napus (leaf 1) (n = 6) | Adaxial | 0.33 ± 0.03 | 0.18 ± 0.03 | 46 | 0.002 |
| Abaxial | 0.63 ± 0.06 | 0.49 ± 0.06 | 22 | 0.073 | |
| Total | 0.96 ± 0.07 | 0.67 ± 0.07 | 31 | 0.007 | |
| B. napus (leaf 2) (n = 6) | Adaxial | 0.39 ± 0.03 | 0.14 ± 0.01 | 65 | <0.001 |
| Abaxial | 0.57 ± 0.07 | 0.58 ± 0.11 | — | NS | |
| Total | 0.96 ± 0.08 | 0.71 ± 0.11 | 26 | 0.045 | |
Measurements on (a) leaves of mature C. communis previously unexposed after 5 d of irradiation (b & c) 1st and 2nd leaves of B. napus cv Apex after growth with 0.63 W m−2 of UV-B radiation. Total gs is the sum of abaxial and adaxial gs. Means ± se are given. P, The probability of difference between treatments from one-tailed t test; NS, P > 0.10.