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Sexual Reproduction in Flowering Plants

NCERT Class 12 Biology Chapter 1

Sexual Reproduction in Flowering Plants for Class 12 Biology and NEET: flower, gametophytes, pollination, double fertilisation, seeds, fruits and apomixis.

5 topics Updated 8 Nov 2026

For: Class 12 and NEET

In the syllabus: NEET Class 12 syllabus

With your textbook

NCERT Biology (Class 12), Chapter 1 “Sexual Reproduction in Flowering Plants”, reprint 2026-27.

Open the official NCERT chapter (PDF, 36.8 MB, ncert.nic.in)

Checked on 19 Oct 2026.

Learn in this order

  1. Flower: a fascinating organ of angiosperms

    Flower structure for Class 12 Biology and NEET: a labelled L.S. diagram, where pollen and embryo sacs form, and sexual reproduction in flowering plants.

    NCERT Section 1.1 8 min read 3 solved examples 6 practice questions

  2. Pre-fertilisation: structures and events

    Pre-fertilisation for Class 12 Biology and NEET: anther, pollen, ovule, embryo sac diagrams, pollination, outbreeding devices, pollen–pistil interaction.

    NCERT Section 1.2 31 min read 6 solved examples 10 practice questions

  3. Double fertilisation

    Double fertilisation for Class 12 Biology and NEET: syngamy and triple fusion with a diagram, zygote and PEN ploidy, and solved chromosome counts.

    NCERT Section 1.3 8 min read 3 solved examples 6 practice questions

  4. Post-fertilisation: structures and events

    Post-fertilisation for Class 12 Biology and NEET: endosperm, embryo, dicot and grass embryos, albuminous seeds, perisperm, false fruits and parthenocarpy.

    NCERT Section 1.4 17 min read 4 solved examples 8 practice questions

  5. Apomixis and polyembryony

    Apomixis and polyembryony for Class 12 Biology and NEET: seeds without fertilisation, nucellar embryos in citrus and mango, and apomixis in hybrid seeds.

    NCERT Section 1.5 9 min read 3 solved examples 7 practice questions

Key formulas in this chapter

Flower: a fascinating organ

  • flower: site of sexual reproduction in angiosperms
  • androecium (stamens) = male; gynoecium (pistil) = female
  • stamen: filament + anther; pistil: stigma + style + ovary
  • anther → pollen grains (male gametophytes)
  • ovule → embryo sac (female gametophyte)
  • end products: fruits and seeds

Pre-fertilisation: structures and events

  • anther: bilobed, dithecous (2 thecae), 4 microsporangia
  • wall: epidermis, endothecium, middle layers, tapetum (nourishes)
  • PMC (2n) undergoes meiosis → microspore tetrad (n) → pollen grains
  • exine: sporopollenin, germ pores; intine: cellulose and pectin
  • MMC (2n) → meiosis → 4 megaspores; 1 functional
  • embryo sac: 3 free-nuclear mitoses, 1 → 2 → 4 → 8 nuclei
  • embryo sac: 7 cells, 8 nuclei
  • xenogamy: pollen from a different plant, the only genetically different pollen
  • monoecy stops autogamy; dioecy stops autogamy and geitonogamy

Double fertilisation

  • syngamy: male gamete (n) + egg (n) → zygote (2n)
  • triple fusion: male gamete (n) + 2 polar nuclei (n + n) → PEN (3n)
  • double fertilisation = syngamy + triple fusion
  • zygote → embryo; PEC → endosperm

Post-fertilisation: structures and events

  • typical pattern: endosperm develops before substantial embryo growth
  • common nuclear type: PEC (3n) → free nuclei → cellular endosperm
  • dicot embryo stages: zygote, proembryo, globular, heart-shaped, mature
  • epicotyl → plumule; hypocotyl → radicle
  • integuments → seed coats; ovary wall → pericarp
  • ovules → seeds; ovary → fruit
  • perisperm = persistent nucellus
  • accessory fruit: tissues beyond ovary contribute; parthenocarpy: fruit without fertilisation

Apomixis and polyembryony

  • apomixis: seed without fertilisation
  • parthenocarpy: fruit without fertilisation
  • polyembryony: more than one embryo in a seed
  • clonal apomictic embryo: maternal genotype (apart from mutation)
  • selfed hybrid: 1/2 Aa; independent loci: 1/4 AaBb

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