# Sexual Reproduction in Flowering Plants Notes | SwaVid Sexual Reproduction in Flowering Plants, NCERT Class 12 Biology: notes with key ideas, key terms, common mistakes and 3 quick checks with worked answers. Canonical: https://www.swavid.com/cbse/class-12/biology/chapter/sexual-reproduction-in-flowering-plants Source: https://www.swavid.com/cbse/class-12/biology/chapter/sexual-reproduction-in-flowering-plants # Sexual Reproduction in Flowering Plants ## Key terms ## Key ideas ## Common mistakes ## Quick checks ## Keep going ## Questions parents ask ## Class 12 Biology on SwaVid ### Structure of stamen and microsporogenesis ### Pistil and megasporogenesis ### Pollination and outbreeding devices ### Pollen-pistil interaction and fertilisation ### Double fertilisation ### Post-fertilisation development ### Apomixis and polyembryony ### Next chapter ### Related chapter ### All chapters SwaVid › CBSE › Class 12 › Biology › Sexual Reproduction in Flowering Plants Notes written by SwaVid from the NCERT textbook. Class 12 Biology, Chapter 1. Key ideas, formulas and common mistakes. CBSE prints 16 marks for Unit VI, not for this chapter alone. Short answer. This chapter explains the structures and events involved in sexual reproduction in angiosperms. It covers microsporogenesis, megasporogenesis, pollination mechanisms, double fertilisation, and post-fertilisation changes leading to seed and fruit formation. Source: NCERT Biology (Reprint 2026-27) , Chapter 1, Sexual Reproduction in Flowering Plants A stamen consists of a filament and a bilobed, dithecous anther containing four microsporangia. Each microsporangium has four wall layers: epidermis, endothecium, middle layers, and a nourishing tapetum. Sporogenous tissue undergoes meiosis to produce microspore tetrads, which dissociate into pollen grains. The gynoecium consists of one or more pistils containing ovules attached to a placenta. A single megaspore mother cell in the nucellus divides meiotically to form four megaspores. In most angiosperms, only one megaspore is functional, developing into an 8-nucleate, 7-celled embryo sac. Pollination transfers pollen grains from the anther to the stigma by wind, water, or animals. It is categorised as autogamy, geitonogamy, or xenogamy depending on the source of pollen. Flowering plants use adaptations like self-incompatibility, non-synchronised pollen release, and unisexual flowers to prevent self-pollination. The pistil recognises compatible pollen and promotes pollen tube growth through the style into an ovule. The pollen tube releases two male gametes into one of the synergids through the filiform apparatus. One male gamete fuses with the egg cell, while the other fuses with the two polar nuclei. Syngamy forms a diploid zygote, and triple fusion produces a triploid primary endosperm nucleus (PEN). Because two types of fusions occur in the same embryo sac, this unique event is termed double fertilisation. The PEN develops into endosperm to provide nutrition to the developing embryo. The zygote forms a proembryo and subsequently develops into a globular, heart-shaped, and mature embryo. The ovules mature into seeds, and the ovary develops into a fruit. Apomixis is a form of asexual reproduction that mimics sexual reproduction by forming seeds without fertilisation. Polyembryony is the occurrence of more than one embryo in a single seed, frequently seen in Citrus and mango. Try each question first. Then tap it to see the answer. Total microspore mother cells = 4 × 25 = 100 Each microspore mother cell forms 4 pollen grains via meiosis Total pollen grains = 100 × 4 = 400 400 pollen grains Root cell is diploid (2n): 2n = 24, so haploid number (n) = 12 Egg cell is haploid (n) = 12 Primary endosperm nucleus is triploid (3n): 3 × 12 = 36 Egg cell: 12, PEN: 36 Formation of 100 pollen grains requires 100 / 4 = 25 meiotic divisions Formation of 100 functional megaspores requires 100 meiotic divisions because 3 degenerate per division Total meiotic divisions = 25 + 100 = 125 125 meiotic divisions Human Reproduction . Principles of Inheritance and Variation . The 13 chapters of Class 12 Biology . CBSE does not give marks to one chapter. It prints 16 marks for Unit VI, Reproduction, which includes Sexual Reproduction in Flowering Plants. No. They are written by SwaVid from the NCERT textbook. The CBSE curriculum is the reference for what is assessed. Human Reproduction. SwaVid is an AI tutor for Indian students in Classes 6 to 12. It finds the earlier ideas a child missed, then teaches today’s chapter. Start free to see how it works. - Ch 1 NCERT book - 16 marks, Unit VI - 3 quick checks - Calling geitonogamy genetically equivalent to xenogamy . Remember that geitonogamy occurs between flowers of the same individual plant, so it is genetically identical to autogamy even though an agent is involved. - Treating the tapetum as a protective outer layer . Identify the tapetum as the innermost layer of the microsporangial wall, which functions primarily to nourish developing microspores and has multinucleated cells. - Assuming endosperm develops after embryo formation . Recognise that endosperm development precedes embryo development because the dividing cells of the endosperm are required to provide assured nutrition to the developing embryo. - Confusing perisperm with pericarp . Use perisperm for residual, persistent nucellus in seeds like black pepper and beet, and pericarp for the wall of the fruit formed from the ovary wall. ## Key Links - [CBSE](https://www.swavid.com/cbse) - [Class 12](https://www.swavid.com/cbse/class-12) - [Biology](https://www.swavid.com/cbse/class-12/biology/chapters) - [Start free →](https://www.swavid.com/signup) - [All 13 chapters](https://www.swavid.com/cbse/class-12/biology/chapters) - [NCERT Biology (Reprint 2026-27)](https://ncert.nic.in/textbook.php) - [Open notes](https://www.swavid.com/cbse/class-12/biology/chapter/human-reproduction) - [Open notes](https://www.swavid.com/cbse/class-12/biology/chapter/principles-of-inheritance-and-variation) - [Class 12 Biology](https://www.swavid.com/cbse/class-12/biology/chapters) - [Start free →](https://www.swavid.com/signup)