REP-01 — Last-Minute 5-Bullet Revision — Summary

Embryo sac = 7 cells, 8 nuclei (1 egg + 2 synergids + central cell with 2 polar nuclei + 3 antipodals); synergids have filiform apparatus; antipodals at chalazal end.
Double fertilization (angiosperms only): syngamy → zygote (2n); triple fusion → PEN (3n); endosperm is TRIPLOID (3n) — never diploid.
Geitonogamy = genetically self-pollination (same plant, no genetic variation), despite being ecologically cross-pollination; xenogamy = true cross between different plants.
Post-fertilization: ovule → seed; ovary → fruit; integuments → seed coat (testa + tegmen); PEN → endosperm (3n); zygote → embryo (2n).
Special modes: apomixis = seeds without fertilization (clones, hybrid vigor); parthenocarpy = seedless fruit (banana); polyembryony = multiple embryos (Citrus).