How Do Organisms Reproduce?
Sexual Reproduction in Plants | Class 10 Science | CBSE + Foundation + Competitive
Sexual Reproduction in Plants
1. Introduction | परिचय
English:
Sexual reproduction in flowering plants involves the formation and fusion of male and female gametes. The reproductive structures of a typical flowering plant are present in the flower. A flower may contain:
हिन्दी:
पुष्पीय पौधों में लैंगिक जनन में नर तथा मादा युग्मकों का निर्माण और उनका संलयन शामिल होता है। पुष्प पौधों की प्रमुख जनन संरचना है।
Sexual reproduction in flowering plants involves the formation and fusion of male and female gametes. The reproductive structures of a typical flowering plant are present in the flower. A flower may contain:
- Male reproductive part – Stamen
- Female reproductive part – Pistil / Carpel
हिन्दी:
पुष्पीय पौधों में लैंगिक जनन में नर तथा मादा युग्मकों का निर्माण और उनका संलयन शामिल होता है। पुष्प पौधों की प्रमुख जनन संरचना है।
Flower
→
Gamete Formation
→
Pollination
→
Fertilisation
→
Seed
→
New Plant
2. Structure of a Flower | पुष्प की संरचना
A typical flower consists of four major whorls:
हिन्दी:
फूल के चार प्रमुख भाग होते हैं—बाह्यदल, पंखुड़ी, पुंकेसर और स्त्रीकेसर।
| Part | Function |
|---|---|
| Sepals | Protect the flower in the bud stage. |
| Petals | Often attract pollinators through colour, scent and other features. |
| Stamen | Male reproductive part; produces pollen grains. |
| Pistil / Carpel | Female reproductive part; contains ovary and ovules. |
3. Animated Flower Diagram | पुष्प का चित्र
🌸 Labelled Flower – Male and Female Reproductive Parts
4. Stamen – Male Reproductive Part | पुंकेसर
The stamen is the male reproductive part of a flower.
It has two main parts:
- Filament: Slender stalk that supports the anther.
- Anther: Produces pollen grains.
Stamen = Filament + Anther
5. Pistil / Carpel – Female Reproductive Part | स्त्रीकेसर
The pistil or carpel is the female reproductive part of a flower.
It consists of:
- Stigma: Sticky surface that receives pollen grains.
- Style: Slender part connecting stigma to ovary.
- Ovary: Contains ovules.
Pistil = Stigma + Style + Ovary
6. Pollen Grains | परागकण
Pollen grains are produced in the anthers.
They carry the male reproductive cells.
When pollen reaches a compatible stigma, it can germinate and form a pollen tube.
The pollen tube grows through the style towards the ovary and helps deliver the male gamete to the ovule.
7. Pollination | परागण
Pollination is the transfer of pollen grains from the anther to the stigma.
There are two major types:
| Type | Meaning |
|---|---|
| Self-pollination | Transfer of pollen to the stigma of the same flower or another flower on the same plant, depending on the context. |
| Cross-pollination | Transfer of pollen from one plant to the stigma of a flower on another plant of the same species. |
8. Agents of Pollination | परागण के माध्यम
Pollen can be transferred by different agents such as:
- Wind
- Water in some aquatic plants
- Insects such as bees and butterflies
- Birds and other animals
9. Pollen Tube Formation | परागनलिका का निर्माण
Animated Pollen Tube Growth
10. Fertilisation | निषेचन
Fertilisation is the fusion of male and female gametes.
In flowering plants, the male gamete delivered through the pollen tube fuses with the egg cell inside the ovule.
The product of fertilisation is called a zygote.
Male Gamete + Female Gamete → Fertilisation → Zygote
Important:
Pollination and fertilisation are not the same process.
Pollination: Transfer of pollen from anther to stigma.
Fertilisation: Fusion of male and female gametes.
Pollination: Transfer of pollen from anther to stigma.
Fertilisation: Fusion of male and female gametes.
11. Changes After Fertilisation | निषेचन के बाद परिवर्तन
| Structure | Develops into |
|---|---|
| Zygote | Embryo |
| Ovule | Seed |
| Ovary | Fruit |
After fertilisation:
- The zygote develops into an embryo.
- The ovule develops into a seed.
- The ovary develops into a fruit.
- Other floral parts may wither or fall off, though some may persist depending on the plant.
12. Formation of Seed | बीज का निर्माण
A seed contains a young developing plant called the embryo along with protective and nutritive structures.
The seed can remain dormant for a period and germinate when suitable conditions are available.
Ovule → Seed → Germination → Seedling → Plant
13. Formation of Fruit | फल का निर्माण
After fertilisation, the ovary generally develops into a fruit.
The fruit protects the seeds and can help in their dispersal.
Different fruits have different structures and adaptations for seed dispersal.
14. Advanced Concept – Double Fertilisation | द्विनिषेचन
Foundation / Competitive Level:
In flowering plants, two fertilisation events occur.
One male gamete fuses with the egg cell to form the zygote.
The other male gamete fuses with the polar nuclei in the central cell to form the primary endosperm nucleus.
This phenomenon is called double fertilisation.
Male Gamete + Egg → Zygote
Male Gamete + Polar Nuclei → Primary Endosperm Nucleus
Male Gamete + Polar Nuclei → Primary Endosperm Nucleus
Competitive Exam Point:
Double fertilisation is a characteristic feature of flowering plants (angiosperms).
15. Self-Pollination and Cross-Pollination
| Self-Pollination | Cross-Pollination |
|---|---|
| Pollen reaches a stigma on the same plant. | Pollen moves from one plant to another plant of the same species. |
| Usually less genetic variation. | Generally promotes greater genetic variation. |
| Does not require pollen transfer between two separate plants. | Requires transfer between different plants. |
16. Sexual vs Asexual Reproduction in Plants
| Asexual Reproduction | Sexual Reproduction |
|---|---|
| Generally one parent. | Male and female gametes participate. |
| No gamete fusion. | Gamete fusion occurs. |
| Generally less variation. | Generally greater variation. |
| Examples: vegetative propagation. | Flowering plant reproduction through pollination and fertilisation. |
17. Importance of Sexual Reproduction | लैंगिक जनन का महत्व
Sexual reproduction is important because it:
- Combines genetic material from two gametes.
- Generates genetic variation.
- Provides variation that can contribute to adaptation and evolution.
- Produces seeds in flowering plants.
- Helps maintain continuity of plant species.
18. MCQs – Multiple Choice Questions
Q1. The male reproductive part of a flower is:
A) Stamen
B) Pistil
C) Ovary
D) Stigma
Answer: A) Stamen
The stamen is the male reproductive part of a flower.
Q2. The female reproductive part of a flower is:
A) Anther
B) Filament
C) Pistil
D) Pollen grain
Answer: C) Pistil
Q3. Pollen grains are produced in the:
A) Ovary
B) Anther
C) Stigma
D) Style
Answer: B) Anther
Q4. The stalk supporting the anther is called:
A) Style
B) Filament
C) Stigma
D) Ovule
Answer: B) Filament
Q5. The sticky part that receives pollen is:
A) Ovary
B) Anther
C) Stigma
D) Filament
Answer: C) Stigma
Q6. The ovules are present inside the:
A) Ovary
B) Anther
C) Filament
D) Stigma
Answer: A) Ovary
Q7. Transfer of pollen from anther to stigma is called:
A) Fertilisation
B) Germination
C) Pollination
D) Fragmentation
Answer: C) Pollination
Q8. Fusion of male and female gametes is called:
A) Pollination
B) Fertilisation
C) Germination
D) Dispersal
Answer: B) Fertilisation
Q9. The product of fertilisation is:
A) Pollen grain
B) Ovule
C) Zygote
D) Fruit
Answer: C) Zygote
Q10. After fertilisation, the ovule generally develops into:
A) Fruit
B) Seed
C) Flower
D) Stigma
Answer: B) Seed
Q11. After fertilisation, the ovary generally develops into:
A) Fruit
B) Seed
C) Pollen
D) Anther
Answer: A) Fruit
Q12. The zygote develops into:
A) Embryo
B) Pollen
C) Stigma
D) Anther
Answer: A) Embryo
Q13. The pollen tube grows through the:
A) Style
B) Anther
C) Filament
D) Sepal
Answer: A) Style
Q14. Which is an agent of pollination?
A) Insects
B) Kidney
C) Neuron
D) Nephron
Answer: A) Insects
Q15. Cross-pollination involves transfer of pollen:
A) Between different plants of the same species
B) From root to leaf
C) From ovary to anther
D) From seed to fruit
Answer: A) Between different plants of the same species
Q16. Which structure contains ovules?
A) Ovary
B) Anther
C) Filament
D) Petal
Answer: A) Ovary
Q17. Which structure produces pollen grains?
A) Stigma
B) Anther
C) Ovary
D) Style
Answer: B) Anther
Q18. Which structure receives pollen grains?
A) Stigma
B) Ovule
C) Anther
D) Filament
Answer: A) Stigma
Q19. Which sequence is correct?
A) Anther → Pollen → Stigma → Pollen Tube → Ovule
B) Ovary → Anther → Seed → Stigma
C) Seed → Pollen → Root → Ovary
D) Stigma → Seed → Anther → Fruit
Answer: A) Anther → Pollen → Stigma → Pollen Tube → Ovule
Q20. Which process directly produces the zygote?
A) Pollination
B) Fertilisation
C) Germination
D) Dispersal
Answer: B) Fertilisation
Q21. Which part connects stigma with ovary?
A) Style
B) Filament
C) Anther
D) Petal
Answer: A) Style
Q22. Which of the following generally produces greater variation?
A) Sexual reproduction
B) Vegetative propagation
C) Cutting
D) Budding
Answer: A) Sexual reproduction
Q23. Double fertilisation is characteristic of:
A) Flowering plants
B) Fungi
C) Bacteria
D) Amoeba
Answer: A) Flowering plants
Q24. In double fertilisation, one male gamete fuses with:
A) Egg cell
B) Pollen grain
C) Stigma
D) Anther
Answer: A) Egg cell
Q25. The second male gamete in double fertilisation fuses with:
A) Polar nuclei
B) Stigma
C) Petal
D) Sepal
Answer: A) Polar nuclei
Q26. Which floral part usually attracts pollinators?
A) Petals
B) Ovule
C) Style
D) Filament
Answer: A) Petals
Q27. Self-pollination generally occurs:
A) On the same plant
B) Only between different species
C) Only through water
D) Only through birds
Answer: A) On the same plant
Q28. The embryo develops from:
A) Zygote
B) Pollen grain
C) Anther
D) Stigma
Answer: A) Zygote
Q29. Which pair is correctly matched?
A) Anther – Pollen
B) Ovary – Pollen grains
C) Stigma – Ovules
D) Filament – Egg cell
Answer: A) Anther – Pollen
Q30. Which sequence correctly represents sexual reproduction in a flowering plant?
A) Pollination → Pollen tube → Fertilisation → Zygote → Seed
B) Seed → Pollination → Anther → Root
C) Fruit → Pollen → Leaf → Fertilisation
D) Root → Flower → Fragmentation → Seed
Answer: A) Pollination → Pollen tube → Fertilisation → Zygote → Seed
19. Subjective Questions with Answers
2 Marks
Q1. What is sexual reproduction in plants?
Sexual reproduction in plants involves the formation and fusion of male and female gametes. In flowering plants, reproduction occurs through flowers.
2 Marks
Q2. Name the male and female reproductive parts of a flower.
Male reproductive part – Stamen.
Female reproductive part – Pistil or Carpel.
Female reproductive part – Pistil or Carpel.
2 Marks
Q3. What is pollination?
Pollination is the transfer of pollen grains from the anther to the stigma of a flower.
2 Marks
Q4. What is fertilisation?
Fertilisation is the fusion of male and female gametes to form a zygote.
2 Marks
Q5. What happens to the ovule and ovary after fertilisation?
The ovule generally develops into a seed and the ovary generally develops into a fruit.
3 Marks
Q6. Describe the structure of a stamen.
A stamen consists of two main parts: filament and anther. The filament supports the anther, while the anther produces pollen grains.
3 Marks
Q7. Describe the structure of a pistil.
The pistil consists of stigma, style and ovary. The stigma receives pollen, the style connects stigma to ovary, and the ovary contains ovules.
3 Marks
Q8. Differentiate between pollination and fertilisation.
Pollination: Transfer of pollen from anther to stigma.
Fertilisation: Fusion of male and female gametes to form a zygote.
Fertilisation: Fusion of male and female gametes to form a zygote.
3 Marks
Q9. What is the function of the pollen tube?
The pollen tube grows from the germinating pollen grain through the style towards the ovule and provides a pathway for the male gamete to reach the female gamete.
3 Marks
Q10. Name three agents of pollination.
Wind, insects and birds are examples of agents of pollination. Water also acts as an agent in some aquatic plants.
4 Marks
Q11. Explain self-pollination and cross-pollination.
Self-pollination involves transfer of pollen to the stigma on the same plant. Cross-pollination involves transfer of pollen from one plant to another plant of the same species. Cross-pollination generally promotes greater genetic variation.
4 Marks
Q12. Explain the role of anther, stigma and ovary.
- Anther: Produces pollen grains.
- Stigma: Receives pollen grains.
- Ovary: Contains ovules where the female reproductive structure is present.
4 Marks
Q13. What changes occur in a flower after fertilisation?
The zygote develops into an embryo, ovules develop into seeds and the ovary generally develops into a fruit. Other floral parts may wither or fall off depending on the plant.
4 Marks
Q14. Why is sexual reproduction important for variation?
Sexual reproduction combines genetic material from male and female gametes. This mixing of genetic information generally produces greater variation among offspring.
4 Marks
Q15. Explain the role of pollinating agents.
Pollinating agents transfer pollen grains from anthers to stigmas. Wind, insects, birds and in some plants water can act as pollinating agents.
5 Marks
Q16. Explain sexual reproduction in flowering plants.
The flower contains male and female reproductive parts. The anther produces pollen grains. Pollination transfers pollen to the stigma. The pollen grain germinates and forms a pollen tube that grows towards the ovule. The male gamete reaches the egg and fuses with it to form a zygote. The zygote develops into an embryo, the ovule becomes a seed and the ovary generally becomes a fruit.
5 Marks
Q17. Explain the structure and functions of the male reproductive part of a flower.
The male reproductive part is the stamen. It consists of filament and anther. The filament is a slender stalk that supports the anther. The anther produces pollen grains, which carry the male reproductive cells.
5 Marks
Q18. Explain the structure and functions of the female reproductive part of a flower.
The female reproductive part is the pistil or carpel. It consists of stigma, style and ovary. The stigma receives pollen, the style provides a path for the pollen tube and the ovary contains ovules.
5 Marks
Q19. Describe the events between pollination and fertilisation.
After pollen reaches a compatible stigma, it germinates and forms a pollen tube. The pollen tube grows through the style towards the ovary and reaches an ovule. The male gamete is delivered to the female gamete, and fusion produces a zygote.
5 Marks
Q20. Differentiate between sexual and asexual reproduction.
| Sexual Reproduction | Asexual Reproduction |
|---|---|
| Involves male and female gametes. | Usually does not involve gamete fusion. |
| Fertilisation occurs. | Fertilisation does not occur. |
| Generally produces greater variation. | Generally produces less variation. |
6 Marks
Q21. Describe the complete process of sexual reproduction in flowering plants.
- The flower contains reproductive structures.
- The anther produces pollen grains.
- Pollination transfers pollen to the stigma.
- The pollen grain germinates and forms a pollen tube.
- The pollen tube grows through the style towards the ovule.
- The male gamete reaches the egg cell.
- Fusion of gametes forms a zygote.
- The zygote develops into an embryo.
- The ovule develops into a seed.
- The ovary generally develops into a fruit.
6 Marks
Q22. Explain pollination and its types.
Pollination is the transfer of pollen grains from anther to stigma.
Self-pollination: Pollen is transferred to a stigma on the same plant.
Cross-pollination: Pollen is transferred from one plant to another plant of the same species.
Cross-pollination generally creates greater genetic variation.
Self-pollination: Pollen is transferred to a stigma on the same plant.
Cross-pollination: Pollen is transferred from one plant to another plant of the same species.
Cross-pollination generally creates greater genetic variation.
6 Marks
Q23. Explain the changes that occur after fertilisation.
- Male and female gametes fuse to form a zygote.
- The zygote develops into an embryo.
- The ovule develops into a seed.
- The ovary generally develops into a fruit.
- The seed contains the developing embryo.
- The seed can later germinate into a new plant under suitable conditions.
6 Marks
Q24. Explain the importance of sexual reproduction in plants.
Sexual reproduction combines genetic material from two gametes and generally creates greater genetic variation. Variation can help populations adapt to changing environments and provides raw material for natural selection and evolution. In flowering plants, sexual reproduction also results in formation of seeds and fruits.
6 Marks
Q25. Explain the role of the flower in sexual reproduction.
The flower contains the reproductive structures of flowering plants. The stamen produces pollen grains, while the pistil contains the ovary and ovules. Pollination transfers pollen to the stigma. The pollen tube carries the male gamete towards the ovule, where fertilisation occurs. After fertilisation, seeds and fruits develop.
6 Marks
Q26. Explain double fertilisation in flowering plants.
In flowering plants, two male gametes participate in two fusion events. One male gamete fuses with the egg cell to form the zygote. The other male gamete fuses with the polar nuclei in the central cell to form the primary endosperm nucleus. This is called double fertilisation.
6 Marks
Q27. Explain how a seed is formed from an ovule.
After fertilisation, the zygote develops into an embryo within the ovule. The ovule undergoes changes and develops into a seed. The seed contains the embryo and protective/nutritive structures. Under suitable conditions, it can germinate and produce a seedling.
6 Marks
Q28. Explain why cross-pollination can increase variation.
Cross-pollination transfers pollen between different plants of the same species. Therefore, genetic material from different parent plants can be combined during sexual reproduction. This generally increases genetic variation among offspring compared with reproduction that involves only one parent.
6 Marks
Q29. Explain the difference between pollination, fertilisation and seed formation.
Pollination: Transfer of pollen from anther to stigma.
Fertilisation: Fusion of male and female gametes to form a zygote.
Seed formation: After fertilisation, the ovule develops into a seed containing the developing embryo.
Fertilisation: Fusion of male and female gametes to form a zygote.
Seed formation: After fertilisation, the ovule develops into a seed containing the developing embryo.
6 Marks
Q30. Write the complete sequence of sexual reproduction in a flowering plant.
Anther
→
Pollen
→
Stigma
→
Pollen Tube
→
Ovule
→
Fertilisation
→
Zygote
→
Embryo
→
Seed
20. HOTS / Competency Based Questions
HOTS 1.
A flower has a healthy ovary and ovules, but pollen grains never reach its stigma. Will fertilisation normally occur? Explain.
Normally, no. Pollination is required to bring pollen to the stigma so that a pollen tube can form and deliver the male gamete to the ovule.
HOTS 2.
Why is the stigma often sticky?
Its sticky surface helps receive and retain pollen grains, increasing the chance that compatible pollen will germinate.
HOTS 3.
A student says, “Pollination and fertilisation are the same thing.” Is the statement correct?
No. Pollination is pollen transfer from anther to stigma, whereas fertilisation is fusion of male and female gametes.
HOTS 4.
If the anther of a flower is removed before pollen release, what reproductive process will be directly affected?
Pollen production/release and therefore pollination will be affected because the anther produces pollen grains.
HOTS 5.
Why can sexual reproduction be important for the long-term survival of a plant population?
It generally produces genetic variation. Some variations may help plants survive changing environmental conditions and can contribute to adaptation and evolution.
21. Important Diagram Labelling
Flower Diagram:
- Petal
- Sepal
- Filament
- Anther
- Stigma
- Style
- Ovary
- Ovule
- Stamen
- Pistil / Carpel
- Stigma
- Style
- Ovary
- Ovule
- Pollen tube
- Male gamete
22. CBSE Golden Points | परीक्षा के लिए महत्वपूर्ण बिंदु
- Flower → reproductive structure of flowering plants.
- Stamen → male reproductive part.
- Pistil/Carpel → female reproductive part.
- Stamen = Filament + Anther.
- Pistil = Stigma + Style + Ovary.
- Anther → produces pollen grains.
- Stigma → receives pollen.
- Ovary → contains ovules.
- Pollination → transfer of pollen from anther to stigma.
- Fertilisation → fusion of male and female gametes.
- Zygote → develops into embryo.
- Ovule → seed.
- Ovary → fruit.
- Self-pollination → same plant.
- Cross-pollination → different plants of same species.
- Sexual reproduction generally produces greater variation.
- Double fertilisation → characteristic of flowering plants.
🧠 Easy Memory Trick
STAMEN → FA
Filament + Anther
PISTIL → SSO
Stigma + Style + Ovary
A → P → S → T → O
Anther → Pollen → Stigma → Tube → Ovule
O → S = Ovule → Seed
O → F = Ovary → Fruit
STAMEN → FA
Filament + Anther
PISTIL → SSO
Stigma + Style + Ovary
A → P → S → T → O
Anther → Pollen → Stigma → Tube → Ovule
O → S = Ovule → Seed
O → F = Ovary → Fruit
23. One-Line Revision | एक पंक्ति में पुनरावृत्ति
Stamen: Filament + Anther → Pollen
Pistil: Stigma + Style + Ovary → Ovules
Pollination: Anther → Stigma
Pollen Tube: Stigma → Style → Ovary → Ovule
Fertilisation: Male Gamete + Egg → Zygote
Post-Fertilisation: Zygote → Embryo; Ovule → Seed; Ovary → Fruit
Pistil: Stigma + Style + Ovary → Ovules
Pollination: Anther → Stigma
Pollen Tube: Stigma → Style → Ovary → Ovule
Fertilisation: Male Gamete + Egg → Zygote
Post-Fertilisation: Zygote → Embryo; Ovule → Seed; Ovary → Fruit
24. Complete Concept Flow
Flower
→
Stamen + Pistil
→
Pollen Formation
→
Pollination
→
Pollen Tube
→
Fertilisation
→
Zygote
→
Embryo
→
Seed
→
New Plant
⭐ Final Exam Revision:
🌸 Flower = reproductive structure
♂️ Stamen = male part
♀️ Pistil = female part
🌾 Anther = pollen
🎯 Stigma = receives pollen
🌱 Ovary = contains ovules
➡️ Pollination = pollen transfer
❤️ Fertilisation = gamete fusion
🧬 Zygote = first cell after fertilisation
🌰 Ovule → Seed
🍎 Ovary → Fruit
🌸 Flower = reproductive structure
♂️ Stamen = male part
♀️ Pistil = female part
🌾 Anther = pollen
🎯 Stigma = receives pollen
🌱 Ovary = contains ovules
➡️ Pollination = pollen transfer
❤️ Fertilisation = gamete fusion
🧬 Zygote = first cell after fertilisation
🌰 Ovule → Seed
🍎 Ovary → Fruit
