Table 3.
Leaf biochemical components and antioxidant enzyme activities in response to different UVA intensities.
| Treatment | Control | UVA-10 | UVA-20 | UVA-30 |
|---|---|---|---|---|
| Total phenolic (mg GAE g−1·FW) | 1.80 ± 0.06b | 1.84 ± 0.07b | 1.99 ± 0.06ab | 2.12 ± 0.08a |
| Total flavonoids (mg RUE g−1·FW) | 6.0 ± 0.3b | 7.3 ± 0.4ab | 8.4 ± 0.6a | 8.9 ± 0.6a |
| Anthocyanin (mg 100 g−1·FW) | 16.0 ± 0.8c | 22.1 ± 0.8ab | 20.5 ± 0.6b | 23.9 ± 1.1a |
| Ascorbic acid (μg g−1·FW) | 204.8 ± 9.5c | 340.2 ± 9.5b | 368.9 ± 4.9a | 329.8 ± 11.5b |
| Total MDA (nmol g−1·FW) | 3.14 ± 0.14b | 3.69 ± 0.17b | 3.53 ± 0.25b | 4.40 ± 0.19a |
| O2 − generation rate (nmol min−1 g−1·FW) | 19.5 ± 0.5c | 20.5 ± 0.6c | 22.8 ± 0.7b | 24.6 ± 0.6a |
| SOD activity1 (U min−1 g−1·FW) | 169.0 ± 2.3b | 181.7 ± 2.5a | 180.5 ± 2.3a | 186.9 ± 2.3a |
| CAT activity2 (U min−1 g−1·FW) | 328.3b ± 3.4 | 366.9 ± 4.1a | 374.8 ± 3.9a | 362.8 ± 2.6a |
| Chl (a + b) (mg m−2) | 612.7 ± 34.0 | 662.5 ± 34.5 | 662.2 ± 29.5 | 682.4 ± 39.2 |
| Carotenoid (mg m−2) | 155.6 ± 9.0 | 166.6 ± 8.9 | 167.3 ± 7.4 | 172.4 ± 9.7 |
| Soluble sugar content (mg g−1·FW) | 15.7 ± 0.5c | 19.8 ± 0.6a | 17.7 ± 0.6b | 17.7 ± 0.8b |
| Total soluble protein (mg g−1·FW) | 5.1 ± 0.3c | 6.3 ± 0.3a | 6.1 ± 0.3ab | 5.8 ± 0.3b |
Data represent mean ± SE (n = 16). Means followed by different letters within one row differ significantly (P < 0.05) as established by the least significant difference test.
150% of the photoreduction of nitroblue tetrazolium (NBT) is used as an enzyme activity unit.
21 nmol of H2O2 degradation per minute is defined as an enzyme activity unit.