Table 1.
Morphology and histology of needles from 2-year-old maritime pine plants derived from somatic embryos matured at 18, 23, or 28 °C (M18, M23, and M28 plants, respectively) that were sampled before (t0) and after (t10) a heat stress treatment for 10 days at 45 °C for 3 h/day. Data are the mean ± SD of at least 10 needles; values followed by the same letter were not significantly different according to Tukey-b (x) or Tamhane (y) tests.
| Plants | Needles Thickness x (µm) |
Epidermis Thickness y (µm) |
Chlorenchyma Thickness x (µm) |
|||
|---|---|---|---|---|---|---|
| t0 | t10 | t0 | t10 | t0 | t10 | |
| M18 | 553 ± 30 b | 651 ± 32 a | 20.3 ± 0.9 a | 18.6 ± 2.3 ab | 143.0 ± 11.8 c | 184.8 ± 13.6 a |
| M23 | 542 ± 42 b | 657 ± 57 a | 18.8 ± 1.4 a | 18.9 ± 1.5 a | 139.8 ± 19.0 c | 159.0 ± 18.3 b |
| M28 | 635 ± 24 a | 557 ± 31 b | 19.1 ± 1.0 a | 16.6 ± 0.8 b | 166.8 ± 9.8 b | 136.4 ± 8.1 c |