Table 1.
Detailed description of the anther and pollen developmental stages of N. nucifera ‘Honghu Hong’.
| Stage | Bud Length (cm) | Anther Length (mm) | Appendage Length (mm) | Pollen Development Stage | Significant Events |
|---|---|---|---|---|---|
| 1 | <1.5 | <1.5 | <0.5 | Sporogenous cell | Formation of four-layered anther wall and pre-meiosis DNA synthesis |
| 2 | 1.5–2.0 | <1.5 | 0.5 | MMC | Formation of microspore mother cells and tapetum layer. Mitosis of tapetal cells |
| 3 | 2.0–2.8 | 2.0–5.0 | <1.0 | Dyads | Meiosis I |
| 4 | 2.8–4.0 | 5.0–6.0 | 1.0–1.5 | Tetrad | Formation of four haploid spores |
| 5 | 4.0–5.0 | 6.0–11.0 | 1.5–3.0 | Early young microspore | Degradation of callose wall. Formation of uninucleated gametophyte and primexine |
| 6 | 5.0–6.0 | 11.0–15.0 | 3.0–4.5 | Middle young microspore | Formation of exine |
| 7 | 6.0–6.5 | 15.0–15.5 | 4.5–5.0 | Late young microspore | Formation of large central vacuoles |
| 8 | 6.5–7.0 | 15.5–16.0 | 5.0 | Early bicellular pollen | Formation of vegetative nucleus and a generative nucleus by pollen mitosis I |
| 9 | 7.0–9.0 | 16.0 | 5.0 | Late bicellular pollen | Formation of intine |
| 10 | 9.0–10.0 | 16.0–16.5 | 5.0 | Mature pollen | Accumulation of starch grains |
| 11 | 10.0 (fully open) | 16.6 | 5.0 | Anther dehiscence | Anther dehiscence and pollen released |