Table 1.
Changes in the flavonol contents during cold acclimation (15/13 °C), chilling (5 °C) and recovery in the leaves and roots of young maize plants. Control: 22/20 °C, 387 µmol m−2 s−1. NA: non-acclimated plants. Light intensities during hardening: GL: 387 µmol m−2 s−1; LL: 107 µmol m−2 s−1. *, **, *** significant differences compared to the control plants on the same day at the p < 0.05, 0.01 and 0.001 levels, respectively. #, ##, ### significant differences compared to the GL plants on the same day at the p < 0.05, 0.01 and 0.001 levels, respectively.
| Leaf | 3 d 15 °C | 3 d 5 °C | 1 d recovery | 4 d recovery | 7 d recovery | ||||||||||
| Control | GL | LL | NA | GL | LL | NA | GL | LL | NA | GL | LL | NA | GL | LL | |
| Kaempferol | 0.76 ± 0.11 | 1.04 ± 0.09 ** | 0.9 ± 0.07 *# | 0.92 ± 0.04 | 0.96 ± 0.16*## | 0.725 ± 0.1 | 1.1 ± 0.46 | 0.96 ± 0.15 | 0.92 ± 0.11 | 2.125 ± 0.44 | 1.04 ± 0.09 *** | 0.96 ± 0.18 *** | 1.4 ± 0.34 | 0.74 ± 0.05 ** | 0.72 ± 0.08 ** |
| Quercetin | 1.43 ± 0.1 | 1.52 ± 0.38 | 1.52 ± 0.16 | 1.76 ± 0.15 | 1.52 ± 0.23 | 1.625 ± 0.17 | 1.66 ± 0.4 | 1.4 ± 0.12 | 1.28 ± 0.13 | 1.42 ± 0.08 | 1.25 ± 0.06 | 1.36 ± 0.29 | 1.12 ± 0.04 | 1.02 ± 0.11 | 0.94 ± 0.15 * |
| Myricetin | 0.31 ± 0.07 | 0.59 ± 0.33 | 0.71 ± 0.42 | 0.24 ± 0.05 | 0.24 ± 0.09 | 0.19 ± 0.22 | nd | 0.58 ± 0.21 *** | 0.65 ± 0.35 ** | nd | nd | nd | nd | 0.43 ± 0.12 *** | 0.3 ± 0.2 * |
| Rutin | 83.28 ± 10.9 | 101.38 ± 8.3 ** | 104.38 ± 7.77 ** | 87.4 ± 10.57 | 97.12 ± 18.51 | 121.83 ± 3.38 ***# | 89.78 ± 6.44 | 82.12 ± 0.82 * | 96.68 ± 5.1 ### | 41.98 ± 15.44 | 31.9 ± 8.24 | 50.28 ± 8.63 # | 37.52 ± 12.59 | 38.54 ± 6.79 | 37.12 ± 3.07 |
| Root | 3 d 15 °C | 3 d 5 °C | 1 d recovery | 4 d recovery | 7 d recovery | ||||||||||
| Control | GL | LL | NA | GL | LL | NA | GL | LL | NA | GL | LL | NA | GL | LL | |
| Kaempferol | 0.04 ± 0.02 | 0.05 ± 0.01 | 0.06 ± 0.02 | 0.13 ± 0.03 | 0.13 ± 0.01 *## | 0.09 ± 0.02 | 0.19 ± 0.03 | 0.16 ± 0.03 | 0.14 ± 0.03 | 0.21 ± 0.03 | 0.25 ± 0.05 | 0.15 ± 0.09 | 0.06 ± 0.02 | 0.04 ± 0.02 | 0.07 ± 0.04 |
| Quercetin | 1.18 ± 0.14 | 1.36 ± 0.06 * | 1.38 ± 0.1 * | 1.36 ± 0.26 | 1.44 ± 0.27 | 1.18 ± 0.16 | 1.45 ± 0.17 | 1.02 ± 0.13 ** | 1.26 ± 0.13# | 1.14 ± 0.11 | 1.2 ± 0.19 | 0.93 ± 0.05**# | 0.8 ± 0.1 | 0.9 ± 0.19 | 1.08 ± 0.08 ** |
| Myricetin | 8.02 ± 0.92 | 26.52 ± 8.99 ** | 29.34 ± 13.61 ** | 11.28 ± 6.04 | 7.76 ± 2.38 | 8.68 ± 6.07 | 4.5 ± 4.6 | 2 ± 1.57 | 2.84 ± 1.8 | 3.28 ± 1.15 | 6.58 ± 2.6* | 7.72 ± 8.01 | 7.94 ± 4.25 | 7.72 ± 1.87 | 11.04 ± 2.9 |
| Rutin | 132.55 ± 18.47 | 130.86 ± 13.14 | 118.8 ± 8.76 | 110.1 ± 6.81 | 105.16 ± 8.88 | 97.18 ± 15.11 | 104.75 ± 2.06 | 97.68 ± 3.48 * | 95.02 ± 6.85 | 106.56 ± 8.13 | 100.44 ± 3.23 | 117.17 ± 20.45 | 126.12 ± 4.68 | 119.36 ± 13.55 | 107.8 ± 12.77 * |