Table 1.
Percentage of nuclei giving 2C, 4C, and S-phase signal of cells of embryonic radicle tips isolated from dry seeds and seeds incubated for various durations at 20 °C with water or with 1mM ABA, or at 30 °C with water with or without 50mM hydroxyurea
Values are mean ± SD of three measurements carried out on 10000 nuclei. The frequency of 2C, 4C, and S-phase nuclei was calculated as [2C nuclei/(2C nuclei + 4C nuclei + S-phase nuclei)] × 100, [4C nuclei/(2C nuclei + 4C nuclei + S-phase nuclei)] × 100, and [S-phase nuclei/(2C nuclei + 4C nuclei + S-phase nuclei)] × 100, respectively. The 2C* population corresponds to nuclei of cells entering S phase but blocked from further DNA synthesis by the presence of 50mM hydroxyurea (Hur). It was integrated to the total amount of nuclei for the hydroxyurea treatments.
| Imbibition time (h) | Treatment | Nuclei (%) in: | 4C/2C | |||
|---|---|---|---|---|---|---|
| 2C | 2C* | 4C | S-phase | |||
| 0 | Dry seed | 82.2±3.1 | 17.1±1.6 | 0.9±1.3 | 0.20 | |
| 18 | Water (20 °C) | 58.1±2.6 | 32.5±1.3 | 9.2±1.4 | 0.56 | |
| 24 | Water (20 °C) | 44.1±2.2 | 44.5±1.8 | 11.3±1.6 | 1.01 | |
| Water + Hur (20 °C) | 46.2±2.3 | 44.1±1.2 | 8.5±1.5 | 2.3±1.5 | 0.09 | |
| ABA (20 °C) | 69.6±1.5 | 26.2±1.9 | 4.3±1.3 | 0.38 | ||
| ABA + Hur (20 °C) | 68.1±2.2 | – | 27.5±1.2 | 5±1.4 | 0.40 | |
| Water (30 °C) | 59.9±2.5 | 30.9±1.5 | 8.8±2.5 | 0.52 | ||
| Water + Hur (30 °C) | 49.1±1.9 | 12.6±1.1 | 37.5±1.8 | 2.3±1.1 | 0.72 | |
| 48 | Water (20 °C) | 34.2±1.9 | 56.8±1.5 | 9.5±1.9 | 1.66 | |
| ABA (20 °C) | 66.5±1.8 | 28.6±2.5 | 4.8±0.9 | 0.43 | ||
| Water (30 °C) | 59.4±1.9 | 29.8±1.8 | 10.6±2.5 | 0.50 | ||
| 72 | Water (20 °C) | – | – | – | – | |
| ABA (20 °C) | 65.3±1.6 | 29.2±1.6 | 5.7±1.0 | 0.44 | ||
| Water (30 °C) | 60.4±2.0 | 30.0±1.8 | 9.6±2.2 | 0.50 | ||