CRITICAL FACTS (Must Know)

Embryo Sac: 7-celled, 8-nucleate

• 1 egg + 2 synergids (micropylar) + 1 central cell (2 polar nuclei) + 3 antipodals (chalazal)

Double Fertilization:

• Syngamy: sperm + egg = ZYGOTE (2n)
• Triple fusion: sperm + 2 polar nuclei = PEN (3n)
• ENDOSPERM = 3n (TRIPLOID) — #1 NEET trap

Pollen grain:

• Exine (outer) = sporopollenin (most resistant biomaterial)
• Intine (inner) = cellulose + pectin (forms pollen tube)
• Germ pores = regions without sporopollenin

Post-fertilization:

• Ovule → Seed | Ovary → Fruit
• Integuments → Seed coat (testa + tegmen)
• PEN → Endosperm (3n) | Zygote → Embryo (2n)

Pollination:

• Autogamy = same flower
• Geitonogamy = same plant (GENETICALLY SELF — no variation)
• Xenogamy = different plants (genetic variation)

Outbreeding devices: Self-incompatibility, Dicliny, Dichogamy

Special reproduction:

• Apomixis = seeds without fertilization (clones)
• Parthenocarpy = seedless fruit (banana)
• Polyembryony = multiple embryos per seed (Citrus)

AVOID THESE MISTAKES

• Never say endosperm is "diploid" → it is TRIPLOID (3n)
• Never say embryo sac has "8 cells" → it has 7 CELLS (8 nuclei)
• Never say geitonogamy promotes variation → it promotes ZERO variation
• Never say cleistogamy is outbreeding → it is INBREEDING