ScienceCBSE Class 9 · Reproduction: How Life Continues

Flower Structure, Pollination, Fertilisation and Gametes (Class 9)

Updated 17 October 2026 · Fact-checked

In a flowering plant the flower is the reproductive organ: stamens (anther and filament) make pollen with male gametes, and the pistil (stigma, style, ovary with ovules) holds the egg cells. Pollination moves pollen from anther to stigma; the pollen grain then grows a pollen tube down the style so that a male gamete fuses with an egg in the ovule (fertilisation), forming a zygote. The ovule becomes the seed and the ovary becomes the fruit. Meiosis halves the chromosome number in gametes (46 to 23 in humans), and fertilisation restores it.

Understand Flower, Pollination, Fertilisation and Gametes

Parts of the flower (outside to inside). Sepals (green) protect the bud; petals (coloured, often scented) attract pollinators; stamens (male) have an anther on a filament, and the anther makes pollen grains containing male gametes; the pistil (female) has a stigma (receives pollen, often sticky), a style (tube) and an ovary holding ovules, each with an egg cell.

Pollination. Pollination is the transfer of pollen from anther to stigma. In pea flowers covered in muslin bags, fruit forms in every set-up except the bud whose stamens were removed before opening, so pollen must reach the stigma for fruit to form. Self-pollination: to the stigma of the same flower or another flower on the same plant (pea, tomato, wheat). Cross-pollination: to a flower on another plant of the same kind (papaya, whose male and female flowers are on different trees); it gives more variation. Agents: wind (small, dull flowers, light dry pollen in huge amounts, long feathery stigma: wheat, maize, rice), water (Vallisneria, Hydrilla), insects (bright, scented flowers with nectar, large sticky pollen, sticky stigma: sunflower, hibiscus, marigold), and birds (bright, often red flowers: coral tree). Wind-pollinated grasses release 5 to 10 lakh pollen grains per flower for 50 to 200 seeds; insect-pollinated sunflower releases 20 000 to 40 000 for 800 to 1000 seeds.

Fertilisation and after. On a compatible stigma the pollen grain germinates and grows a pollen tube down the style into the ovary; the male gamete travels down the tube to the ovule and fuses with the egg cell. This is fertilisation, forming the zygote, which grows into an embryo. The ovule becomes the seed and the ovary becomes the fruit; petals and stamens usually wither. The order is: pollination, pollen germination on the stigma, pollen tube growth, fertilisation, zygote, embryo, seed and fruit.

Seed dispersal and germination. Seeds are spread by wind (light, winged or hairy seeds: madar, dandelion), water (coconut) or animals (hooks, fleshy fruits). With water, air and a suitable temperature the seed germinates.

Chromosomes, meiosis and variation. Chromosomes are thread-like structures in the nucleus that carry genetic information; the number is fixed for a species. Humans have 23 pairs (46), one of each pair from each parent. Meiosis halves the number from diploid (2n) to haploid (n) in gametes, so that fertilisation restores the full number in the zygote; otherwise the number would double every generation. In plants the male gametes are in pollen and the egg is in the ovule. During meiosis the two chromosomes of each pair separate randomly, so with n pairs there are 2ⁿ possible gamete combinations from one parent (3 pairs give 2³ = 8; 23 pairs give 2²³ = 8 388 608). The zygote combines one gamete from each parent. Variation helps the species survive changing conditions.

Plant breeding. Selective breeding and artificial hybridisation (remove the stamens from a bud, bag the flower, dust chosen pollen by hand) give high-yielding and disease-resistant varieties. P. Maheshwari, the Father of Indian Embryology, grew plant embryos in a test tube.

Flower, Pollination, Fertilisation and Gametes: formulas and key facts

Flower whorls: Sepals
petals
stamens (anther + filament)
pistil (stigma + style + ovary with ovules)
After fertilisation: $O v u l e \to see d ∣ o v a r y \to f r u i t ∣ z y g o t e \to e mb r y o$
Sequence in a plant: 1.Pollination
2.pollen tube
3.fertilisation
4.zygote
5.seed and fruit
6.dispersal
7.germination
Chromosome numbers in humans: $B o d y ce l l 46 (23 p ai r s) ∣ g am e t es 23∣ z y g o t e 23 + 23 = 46$
Gamete combinations: $n p ai r s g i v e 2^{n} co mbina t i o n s p er p a r e n t ∣ z y g o t eco mbina t i o n s = 2^{n} \times 2^{n} = 4^{n}$

How to solve Flower, Pollination, Fertilisation and Gametes questions

Use this method for flower, pollination and fertilisation questions.

1Name the part from its position and job: sepal (protect), petal (attract), anther (pollen), stigma (receives pollen), style (tube), ovary (ovules and later fruit).
2Decide whether pollination is self or cross by asking whether the pollen goes to the same plant or to another plant of the same kind.
3Match the pollinating agent with the flower features: small and dull with feathery stigma means wind; bright and scented means insects or birds.
4Write the sequence from pollination to seed and give what each part becomes.
5For numbers of chromosomes, halve at meiosis and double at fertilisation; for combinations use 2ⁿ.
6For pollen-per-seed questions divide the pollen number by the seed number.

Flower, Pollination, Fertilisation and Gametes in real life

Each concept, met in an everyday situation. Read the situation, try the problem, then check the solution. The one-line hook is what to remember.

Why wheat flowers are plain and sunflowers are showy

Suppose a student compares a wheat flower and a sunflower and notes that wheat makes huge amounts of fine, dry pollen while sunflower makes less, large, sticky pollen.

Explain the difference in terms of the pollinating agent, using the chapter's figures of 5 to 10 lakh pollen grains per flower for 50 to 200 seeds in grasses.

Try it first, then show the solutionSolution

Wheat is wind-pollinated; much pollen is wasted in the air, so a very large number of light grains are needed to reach the long feathery stigma.
Sunflower is insect-pollinated; bright petals and nectar attract insects that carry sticky pollen directly, so fewer grains (20 000 to 40 000) suffice for 800 to 1000 seeds.
Wheat has about 5 lakh ÷ 200 = 2500 to 10 lakh ÷ 50 = 20 000 grains per seed, whereas sunflower has only about 20 to 50 per seed.

Answer: Wind wastes pollen, so wheat makes far more of it; insects deliver it accurately.

Memory hook: Wind wastes, insects deliver.

Which part of a mango flower becomes the fruit?

Suppose a child asks why a mango has a hard stone in the middle and a sweet pulp around it, and where each came from.

Name the flower parts that became the seed and the fruit after fertilisation.

Try it first, then show the solutionSolution

The male gamete from the pollen tube fuses with the egg in the ovule, forming a zygote, which grows into an embryo.
The ovule with its embryo becomes the seed (inside the stone).
The ovary becomes the fruit; petals and stamens wither.

Answer: Ovule becomes the seed; ovary becomes the fruit.

Memory hook: Ovule is the seed, ovary is the fruit.

Tricks to remember Flower, Pollination, Fertilisation and Gametes

Short memory aids. Say each one aloud once, then use it on a question the same day.

OV-ule to seed, OV-ary to fruit
Ovule becomes the seed. Ovary becomes the fruit. Both begin with 'ov'.
Use it when: Fate of flower parts after fertilisation.
Stigma sticky, style tube, ovary base
Pollen lands on the stigma, travels down the style and reaches the ovary: top to bottom.
Use it when: Path of the pollen tube.
Halve then double
Meiosis halves chromosomes in gametes (46 to 23); fertilisation doubles them back (23 + 23 = 46).
Use it when: Chromosome number questions.
Dull and dusty means wind
Wind: small dull flowers, lots of dry pollen, feathery stigma. Insects: bright, scented, sticky pollen.
Use it when: Matching flowers and pollinators.

Flower, Pollination, Fertilisation and Gametes: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Parts of a flower and their functions · 3 marks · Short answerBoard level

Name the part of the flower that (a) protects the bud, (b) attracts insects, (c) produces pollen, (d) receives the pollen. Also name the two parts of the stamen.

Try it first, then show the solutionSolution

(a) Sepals protect the bud and (b) petals attract insects by colour and scent. (1)
(c) The anther produces pollen grains; (d) the stigma of the pistil receives them. (1)
The stamen has an anther and a filament (a stalk). (1)

Answer: (a) sepals; (b) petals; (c) anther; (d) stigma; anther and filament.

Example 2: From pollination to seed · 3 marks · Short answerBoard level

(a) Define pollination and name the two kinds. (1)
(b) List in order the events from pollination to the formation of the seed. (1)
(c) What do the ovule, the ovary and the zygote become? (1)

Try it first, then show the solutionSolution

(a) Pollination is the transfer of pollen from the anther to the stigma; it can be self-pollination or cross-pollination. (1)
(b) Pollen lands on the stigma, the pollen grain germinates, the pollen tube grows through the style to the ovule, the male gamete fuses with the egg (fertilisation), forming the zygote, which grows into an embryo. (1)
(c) The ovule becomes the seed, the ovary becomes the fruit, and the zygote becomes the embryo. (1)

Answer: (a) anther to stigma; self and cross; (b) pollen tube, fertilisation, zygote, embryo, seed; (c) seed, fruit, embryo.

Example 3: Pollen per seed in wind and insect pollination · 5 marks · Long answerHarder board level

Wind-pollinated grasses release 5 to 10 lakh pollen grains per flower for 50 to 200 seeds, and insect-pollinated sunflower releases 20 000 to 40 000 grains for 800 to 1000 seeds. (1 lakh = 100 000.)
(a) Find the smallest and largest number of pollen grains per seed for the grass. (2)
(b) Find the smallest and largest number per seed for the sunflower. (1)
(c) Show that the grass needs at least 50 times as many grains per seed as the sunflower. (1)
(d) Name two features of a wind-pollinated flower that suit it. (1)

Try it first, then show the solutionSolution

(a) Smallest: 5 lakh ÷ 200 = 500 000 ÷ 200 = 2500. Largest: 10 lakh ÷ 50 = 1 000 000 ÷ 50 = 20 000. (2)
(b) Smallest: 20 000 ÷ 1000 = 20. Largest: 40 000 ÷ 800 = 50. (1)
(c) Smallest for grass ÷ largest for sunflower = 2500 ÷ 50 = 50, so the grass needs at least 50 times as many grains per seed. (1)
(d) Small, dull flowers that make a large amount of light, dry pollen, and a long feathery stigma to catch pollen from the air. (1)

Answer: (a) 2500 to 20 000; (b) 20 to 50; (c) 2500 ÷ 50 = 50; (d) light dry pollen and a feathery stigma.

Example 4: Chromosomes, meiosis and variation · 5 marks · Long answerHarder board level

(a) A species has 3 pairs of chromosomes. How many different gametes can one parent make from the combinations of chromosomes? (1)
(b) How many different zygotes are possible from two such parents? (1)
(c) Humans have 23 pairs of chromosomes; find the number of different gametes one person can produce, from 2²³. (1)
(d) Why must the number of chromosomes be halved in gametes? (1)
(e) Why does sexual reproduction give variation but vegetative propagation does not? (1)

Try it first, then show the solutionSolution

(a) 2³ = 8 gamete types. (1)
(b) Each parent makes 8 types, so zygotes = 8 × 8 = 64. (1)
(c) 2²³ = 8 388 608 (over 8 million). (1)
(d) At fertilisation the male and female gametes fuse; if each carried 46, the zygote would have 92 and the number would double every generation. With 23 in each gamete, the zygote has 23 + 23 = 46. (1)
(e) In sexual reproduction, meiosis separates chromosome pairs randomly and fertilisation combines two different gametes, so every offspring has a new mixture; vegetative propagation uses mitosis from one parent, so offspring are identical clones. (1)

Answer: (a) 8; (b) 64; (c) 8 388 608; (d) to keep 46 in the zygote; (e) random separation and mixing of two parents' gametes.

Example 5: A bagged pea flower and a hybrid · 4 marks · Case-basedHOTS / competency

In an experiment with pea plants, four flowers are treated: A is left open; B is bagged with its stamens intact; C is a bud whose stamens are removed before opening and which is then bagged; D has its stamens removed, is dusted with pollen from another plant by hand, and is bagged. A pod of the fruit that forms has 8 ovules and pollen tubes reach 6 of them.
(a) Which flowers will form fruit and which will not? (1)
(b) What does the result for C show? (1)
(c) Name the kind of pollination in B and in D. (1)
(d) What percentage of ovules were fertilised in the pod, and how many seeds form? (1)

Try it first, then show the solutionSolution

(a) A, B and D form fruit; C does not. (1)
(b) Without pollen reaching the stigma there is no fertilisation, so no fruit forms: pollination is needed. (1)
(c) B shows self-pollination; D shows cross-pollination (artificial hybridisation). (1)
(d) 6 ÷ 8 × 100 = 75% of the ovules are fertilised, so 6 seeds form (each fertilised ovule becomes a seed). (1)

Answer: (a) A, B, D fruit and C does not; (b) pollination is needed; (c) self in B, cross in D; (d) 75% and 6 seeds.

Where students lose marks in Flower, Pollination, Fertilisation and Gametes

The slips examiners see most often, and what to write instead.

Mistake: Saying the ovary becomes the seed.
Ovary and ovule are confused.
Wrong working
Ovary becomes the seed and ovule becomes the fruit.
Right working
Ovule becomes the seed; ovary becomes the fruit.
Do this: The ovule is the small structure inside the ovary; it becomes the seed, and the ovary around it becomes the fruit.
Usually costs: 1 mark.
Mistake: Defining pollination as the fusion of male and female gametes.
Pollination and fertilisation are confused.
Wrong working
Pollination is the fusion of the sperm and the egg.
Right working
Pollination is the transfer of pollen from the anther to the stigma; fertilisation is the fusion of gametes.
Do this: Transfer first, fusion later.
Usually costs: 1 mark.
Mistake: Writing that wind-pollinated flowers have bright petals and nectar.
All flowers are assumed to attract insects.
Wrong working
Wheat has bright scented petals to attract insects.
Right working
Wheat flowers are small and dull, with light dry pollen and a feathery stigma.
Do this: Match features with the agent.
Usually costs: 1 mark.
Mistake: Using 2n as 2 × n for gamete combinations.
The index is confused with a multiplier.
Wrong working
3 pairs give 2 × 3 = 6 gametes.
Right working
3 pairs give 2³ = 8.
Do this: Combinations double with each extra pair.
Usually costs: 1 mark.
Mistake: Saying meiosis makes gametes with the same chromosome number as body cells.
Mitosis and meiosis are confused.
Wrong working
Gametes have 46 chromosomes.
Right working
Gametes have 23 chromosomes (half) so the zygote has 46.
Do this: Meiosis halves; fertilisation restores.
Usually costs: 1 mark.

Exam tips

Label the flower with sepals, petals, anther, filament, stigma, style, ovary and ovule; draw leader lines without crossing.
Write the sequence pollination, pollen tube, fertilisation, zygote, seed and fruit in order.
Use technical words: pollen tube, male gamete, egg, zygote, embryo.
Show 2ⁿ on a separate line in variation questions.
Give the agent and flower features together when asked about wind, insect, bird or water pollination.

Practice questions on Flower, Pollination, Fertilisation and Gametes

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 2 marks · Very short answerBoard level
In artificial hybridisation the stamens are removed from the bud and the flower is bagged. Give the purpose of each step.
Hint
Think of what could reach the stigma.
Answer
Removing the stamens before the flower opens prevents self-pollination (1 mark). Bagging the flower keeps out unwanted pollen until the chosen pollen is dusted on the stigma by hand (1 mark).
Q2 · 3 marks · Short answerHarder board level
A grass flower releases 8 lakh pollen grains and forms 100 seeds, and a sunflower releases 30 000 grains and forms 900 seeds. (a) Find the pollen grains per seed for each. (b) How many times larger is the grass figure? (c) Explain the difference.
Hint
8 lakh = 800 000.
Answer
(a) Grass: 800 000 ÷ 100 = 8000 grains per seed; sunflower: 30 000 ÷ 900 = 33.3 grains per seed (1 mark). (b) 8000 ÷ 33.3 = 240 times (1 mark). (c) Wind scatters pollen and wastes most of it, so grasses need huge numbers, while insects carry sticky pollen directly to flowers, so far fewer grains are needed (1 mark).
Q3 · 2 marks · Assertion-reasonBoard level
Assertion (A): Flowers pollinated by wind are usually small and dull. Reason (R): They do not need to attract insects or birds. Choose: (a) A and R both true, R explains A; (b) A and R both true, R does not explain A; (c) A true, R false; (d) A false, R true.
Hint
Why would bright petals be wasted on a wind-pollinated plant?
Answer
(a). Wind carries the pollen, so there is no need to attract animals with bright petals, scent or nectar.
Q4 · 3 marks · Short answerHarder board level
Name the part of the plant that (a) becomes the seed, (b) becomes the fruit, (c) forms the tube through which the male gamete travels. Why do the petals and stamens usually wither after fertilisation? Give two ways in which seeds are dispersed by animals or wind.
Hint
Think of the fate of each flower part.
Answer
(a) Ovule; (b) ovary; (c) the pollen tube, which grows from the pollen grain through the style (1 mark). Petals and stamens have done their work (attracting pollinators and giving pollen) and are no longer needed (1 mark). Wind: light, winged or hairy seeds (madar, dandelion); animals: hooks or fleshy fruits (1 mark).
Q5 · 4 marks · Case-basedHOTS / competency
A breeder wants to cross two varieties of a plant that has 6 pairs of chromosomes. (a) Describe the steps of artificial hybridisation. (b) How many different gametes can each parent make? (c) How many different zygotes are possible from a cross between them? (d) Why is a hybrid produced by seed more variable than a plant produced by cutting?
Hint
Use 2ⁿ for gametes.
Answer
(a) Remove the stamens from the flower of the female parent in the bud stage, cover (bag) the flower, then dust the stigma by hand with pollen from the chosen male parent and bag it again (1 mark). (b) 2⁶ = 64 (1 mark). (c) 64 × 64 = 4096 (1 mark). (d) Seeds come from fertilisation of gametes made by meiosis, which shuffles the chromosomes, whereas a cutting is a clone made by mitosis (1 mark).

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.What does the anther produce?Show answer
Pollen grains containing the male gametes.
2.Which part of the pistil receives pollen?Show answer
The stigma.
3.What does the zygote grow into?Show answer
The embryo.
4.How many gamete combinations can a plant with 4 chromosome pairs produce?Show answer
2⁴ = 16.
5.Name two wind-pollinated crops.Show answer
Wheat and maize (also rice).
6.Which scientist is called the Father of Indian Embryology?Show answer
P. Maheshwari.

Flower, Pollination, Fertilisation and Gametes: frequently asked questions

Is pollination the same as fertilisation?

No. Pollination is the transfer of pollen to the stigma; fertilisation happens later, when the male gamete fuses with the egg in the ovule.

Why do most flowers have a sticky stigma?

The stickiness holds the pollen grains that land on it so they can germinate.

What is the role of the pollen tube?

It carries the male gamete from the pollen grain through the style to the ovule.

Why is cross-pollination useful?

It mixes the genes of two plants, giving more variation, which helps the species survive changes.

Do all pollen grains develop into seeds?

No. Only the grains whose male gametes fertilise an egg lead to a seed; many are wasted, especially in wind-pollinated plants.