Reproduction in flowering plants is one of the most important chapters of Class 12 Biology and plays a crucial role in Board examinations, NEET, and CUET. This chapter explains how flowering plants reproduce, starting from flower structure to seed and fruit formation. Students often find this chapter lengthy, but with clear concepts, proper diagrams, and step-by-step explanations, it becomes easy to understand and score high marks.
In these Reproduction in Flowering Plants Class 12 Notes, all topics are explained in simple language, strictly based on NCERT, and presented in a way that helps students revise quickly before exams.
Reproduction in Flowering Plants Class 12 Notes PDF | NCERT Biology
What is Reproduction?
Reproduction is the biological process by which organisms produce new individuals of their own kind. In flowering plants, reproduction occurs mainly through sexual reproduction, which involves the formation and fusion of male and female gametes.
Types of Reproduction in Flowering Plants
Flowering plants show two main types of reproduction:
1. Asexual Reproduction
- Occurs without fusion of gametes
- Offspring are genetically identical to parent
- Examples: vegetative propagation, apomixis
2. Sexual Reproduction
- Involves formation of male and female gametes
- Fusion of gametes leads to zygote formation
- Results in genetic variation
Structure of a Flower
A flower is the reproductive unit of a flowering plant. It consists of four whorls:
1. Calyx
- Outermost whorl
- Made up of sepals
- Protects the flower bud
2. Corolla
- Composed of petals
- Usually bright coloured
- Attracts insects for pollination
3. Androecium (Male Reproductive Part)
- Consists of stamens
- Each stamen has:
- Anther – produces pollen grains
- Filament – supports the anther
4. Gynoecium (Female Reproductive Part)
- Composed of pistil/carpel
- Parts of pistil:
- Stigma – receives pollen
- Style – connects stigma to ovary
- Ovary – contains ovules
Microsporogenesis (Formation of Pollen Grains)
Microsporogenesis is the process of formation of microspores (pollen grains) from microspore mother cells.
- Occurs inside anther
- Anther has four microsporangia
- Microspore mother cells undergo meiosis
- Each cell forms four haploid microspores
Structure of Pollen Grain
- Exine – tough outer layer made of sporopollenin
- Intine – inner thin wall
- Contains:
- Vegetative cell
- Generative cell
Megasporogenesis (Formation of Ovule)
Megasporogenesis is the process of formation of megaspore from megaspore mother cell.
- Occurs inside ovule
- Megaspore mother cell undergoes meiosis
- Produces four megaspores
- Only one functional megaspore survives
Embryo Sac (Female Gametophyte)
The functional megaspore develops into an embryo sac.
Structure of Embryo Sac
- 7 cells and 8 nuclei
- Parts:
- Egg cell
- Two synergids
- Three antipodal cells
- Two polar nuclei
Pollination
Pollination is the transfer of pollen grains from anther to stigma.
Types of Pollination
1. Self Pollination
- Same flower or same plant
- Types:
- Autogamy
- Geitonogamy
2. Cross Pollination
- Between flowers of different plants
- Also called xenogamy
Agents of Pollination
- Wind (anemophily)
- Water (hydrophily)
- Insects (entomophily)
- Birds and animals
Outbreeding Devices
To prevent self-pollination, plants show outbreeding devices such as:
- Dichogamy
- Herkogamy
- Self-incompatibility
- Unisexual flowers
Pollen–Pistil Interaction
After pollination:
- Pollen grain germinates on stigma
- Pollen tube grows through style
- Male gametes reach ovule
This interaction ensures compatibility between pollen and pistil.
Fertilization in Flowering Plants
Flowering plants show double fertilization, which is unique to angiosperms.
Types of Fertilization
- Syngamy
- Fusion of male gamete with egg
- Forms zygote
- Triple Fusion
- Fusion of male gamete with two polar nuclei
- Forms primary endosperm nucleus
Post-Fertilization Changes
Development of Embryo
- Zygote develops into embryo
- Parts:
- Radicle
- Plumule
- Cotyledons
Development of Endosperm
- Provides nourishment to embryo
- Types:
- Nuclear
- Cellular
- Helobial
Development of Seed
- Ovule → Seed
- Integuments → Seed coat
Development of Fruit
- Ovary → Fruit
- Ovary wall → Pericarp
Apomixis
Apomixis is the formation of seeds without fertilization.
- Seen in grasses and citrus
- Useful in agriculture
- Produces genetically identical plants
Polyembryony
Formation of more than one embryo in a single seed.
- Example: Citrus
- Important in plant breeding
Importance of Reproduction in Flowering Plants
- Ensures continuity of species
- Maintains genetic diversity
- Important for agriculture and food production
Important Exam-Oriented Questions
- Define double fertilization.
- Draw a labelled diagram of pollen grain.
- Explain structure of embryo sac.
- What is apomixis? Write its advantages.
- Differentiate between self and cross pollination.
Why These Notes Are Best for Students?
- NCERT-based explanation
- Simple and clear language
- Board + NEET focused
- Covers all diagrams & keywords
- Perfect for revision
Conclusion
Reproduction in Flowering Plants Class 12 Notes is a high-scoring chapter if prepared properly. Understanding concepts like pollination, fertilization, embryo formation, and seed development is essential for exams. These notes provide a complete, structured, and exam-oriented explanation that helps students revise quickly and confidently.
FAQs
Reproduction in Flowering Plants Class 12
1. What is reproduction in flowering plants in Class 12 Biology?
Reproduction in flowering plants refers to the process by which angiosperms produce new plants through sexual reproduction, involving pollination, fertilization, seed formation, and fruit development.
2. Why is double fertilization unique to flowering plants?
Double fertilization is unique to flowering plants because two fusion events occur:
- One male gamete fuses with egg (syngamy)
- Another male gamete fuses with polar nuclei (triple fusion)
This results in the formation of embryo and endosperm simultaneously.
3. Is Reproduction in Flowering Plants important for NEET and board exams?
Yes, this chapter is very important for:
- Class 12 Board Exams
- NEET Biology
- CUET
Questions are frequently asked from pollination, fertilization, embryo sac, and diagrams.
4. What are the most important topics in Reproduction in Flowering Plants?
The most important topics are:
- Structure of flower
- Microsporogenesis and megasporogenesis
- Pollination and its types
- Double fertilization
- Development of seed and fruit
- Apomixis and polyembryony
5. What is pollen–pistil interaction?
Pollen–pistil interaction is the process where the pistil recognizes compatible pollen and allows pollen tube growth for successful fertilization.
6. What is apomixis in flowering plants?
Apomixis is the formation of seeds without fertilization, producing offspring genetically identical to the parent plant. It is common in grasses and citrus plants.
7. How many cells are present in the embryo sac?
A mature embryo sac contains 7 cells and 8 nuclei, including:
- 1 egg cell
- 2 synergids
- 3 antipodal cells
- 2 polar nuclei
8. What is the difference between pollination and fertilization?
- Pollination is the transfer of pollen from anther to stigma
- Fertilization is the fusion of male and female gametes
Both processes are essential for seed formation.
9. What diagrams are important from this chapter?
Important diagrams include:
- Structure of flower
- Pollen grain
- Embryo sac
- L.S. of ovule
- Double fertilization
10. Where can I download Reproduction in Flowering Plants Class 12 Notes PDF?
Students usually search for NCERT-based Reproduction in Flowering Plants Class 12 Notes PDF on educational websites and blogs that provide free, exam-oriented study material.