Embryo Sac Diagram
Numbered Labels
| Label | Structure | Details |
|---|---|---|
| 1 | Micropyle | Opening at base of ovule through which pollen tube enters |
| 2 | Egg cell (n) | Haploid female gamete; undergoes syngamy with sperm → zygote (2n) |
| 3 | Synergid 1 (n) | Left synergid; has filiform apparatus; one degenerates on pollen tube entry |
| 4 | Synergid 2 (n) | Right synergid; has filiform apparatus |
| 5 | Filiform apparatus | Wall ingrowth of synergids; secretes chemotropic signals to guide pollen tube |
| 6 | Central cell | Largest cell of embryo sac; contains 2 polar nuclei (each n) |
| 7 | Polar nucleus 1 (n) | Participates in triple fusion with Sperm 2 and Polar nucleus 2 |
| 8 | Polar nucleus 2 (n) | Participates in triple fusion |
| 9 | Antipodal cell 1 (n) | Nutritive; chalazal end; degenerates after fertilization |
| 10 | Antipodal cell 2 (n) | Nutritive; chalazal end |
| 11 | Antipodal cell 3 (n) | Nutritive; chalazal end |
| 12 | Chalazal end | End opposite to micropyle; location of antipodals |
| 13 | Nucellus | Sporophytic (2n) tissue surrounding embryo sac; provides nutrition during development |
| 14 | Integuments (2) | Two layers surrounding ovule; develop into testa (outer) and tegmen (inner) after fertilization |