Table 4.
Cytokinin content in needles of maritime pine plants derived from somatic embryos matured at different temperatures (18, 23, or 28 °C) that were employed in a heat stress experiment for 10 days at 45 °C for 3 h/day. Plants were sampled at the beginning of the stress treatment (t0), at the end of the stress treatment (t10), and after a recovery period of a further 10 days (tR). Data are the mean ± SE of six replicates and 22 compounds grouped by conjugated structure, and the percentages refer to total CK content.
| Plants | Time | Active Forms | Transport Forms | Precursors | Reversible Metabolites | Irreversible Metabolites | Total CK y |
|---|---|---|---|---|---|---|---|
| CKs Bases x | CK Ribosides y | CK Nucleotides y | CK O-glucosides y | CK N-glucosides y | |||
| M18 | t0 | 0.16 ± 0.03 (2.4%) a | 0.06 ± 0.01 (0.9%) b | 0.20 ± 0.02 (3.0%) a | 6.28 ± 0.17 (93.3%) a | 0.03 ± 0.00 (0.4%) a | 6.73 ± 0.18 a |
| t10 | 0.16 ± 0.03 (7.1%) a | 0.13 ± 0.02 (5.9%) ab | 0.09 ± 0.01 (3.0%) b | 1.89 ± 0.21 (82.6) b | 0.01 ± 0.00 (0.5%) ab | 2.28 ± 0.26 b | |
| tR | 0.18 ± 0.03 (5.3%) a | 0.24 ± 0.03 (7.1%) a | 0.16 ± 0.01 (4.8%) ab | 2.74 ± 0.06 (82.6%) ab | 0.01 ± 0.00 (0.2%) b | 3.31 ± 0.11 ab | |
| M23 | t0 | 0.12 ± 0.04 (2.2%) b | 0.05 ± 0.01 (0.9%) b | 0.20 ± 0.04 (3.6%) b | 5.07 ± 0.09 (92.8%) ab | 0.03 ± 0.02 (0.5%) ab | 5.46 ± 0.13 ab |
| t10 | 0.12 ± 0.01 (2.4%) b | 0.29 ± 0.03 (5.9%) a | 0.59 ± 0.09 (12.0%) a | 3.93 ± 0.37 (79.6%) b | 0.01 ± 0.00 (0.1%) b | 4.94 ± 0.47 b | |
| tR | 0.17 ± 0.02 (1.5%) a | 0.09 ± 0.00 (0.8%) ab | 0.29 ± 0.07 (2.5%) ab | 10.92 ± 1.48 (94.9%) a | 0.04 ± 0.01 (0.3%) a | 11.50± 1.55 a | |
| M28 | t0 | 0.21 ± 0.06 (1.6%) a | 0.04 ± 0.02 (0.3%) b | 0.14 ± 0.04 (1.1%) b | 12.82 ± 2.04 (96.7%) a | 0.04 ± 0.01 (0.3%) a | 13.25 ± 2.15 a |
| t10 | 0.17 ± 0.04 (3.5%) a | 0.33 ± 0.02 (6.9%) a | 0.41 ± 0.08 (8.4%) a | 3.94 ± 0.42 (81.1%) b | 0.01 ± 0.02 (0.1%) b | 4.86 ± 0.48 b | |
| tR | 0.09 ± 0.02 (1.0%) b | 0.07 ± 0.00 (0.7%) ab | 0.20 ± 0.03 (2.0%) ab | 9.24 ± 0.62 (96.0%) ab | 0.03 ± 0.00 (0.3%) ab | 9.63 ± 0.60 ab |
x, mean separation within each group of plants according to the Tukey-b test. y, mean separation within each group of plants according to the Kruskal-Wallis test with Bonferroni correction for multiple comparisons.