ScienceCBSE Class 9 · Reproduction: How Life Continues

Asexual Reproduction: Vegetative Propagation, Budding and Spores (Class 9)

Updated 17 October 2026 · Fact-checked

In asexual reproduction a single parent produces genetically identical offspring (clones) by mitosis, without gametes. It includes vegetative propagation from roots, stems or leaves (naturally in potato, ginger, money plant, sugarcane and Bryophyllum; artificially by cutting, grafting, layering and tissue culture), budding (yeast, Hydra) and spore formation (Rhizopus and other moulds). It is fast and keeps desirable qualities, but gives no variation, so one disease can destroy a whole crop.

Understand Asexual Reproduction and Vegetative Propagation

Reproduction. Reproduction produces new individuals of the same kind and keeps a species going though each individual has a limited life span. In asexual reproduction there is one parent, no gametes, cell division is by mitosis, and offspring are genetically identical (clones); it is fast, as in bacteria, Amoeba, yeast, Hydra, sponges and many plants. In sexual reproduction there are two parents, gametes made by meiosis, and the offspring show variation.

Vegetative propagation. New plants grow from vegetative parts (root, stem, leaf), not from seeds. Natural examples: the eyes (buds) on the underground stem of potato and ginger; nodes on stem pieces of money plant and sugarcane; plantlets that grow from the leaf margins of Bryophyllum. Artificial methods: (1) Cutting: a piece of stem with nodes is planted with the lower leaves removed, buried about half its length at 45° to 60°, and kept moist (rose, money plant, sugarcane). (2) Grafting: a shoot (scion) of the desired variety is fitted into a slit in a rooted plant (stock), bound and protected until it heals (mango, roses, citrus). (3) Layering: a flexible branch (lemon, jasmine) is bent and its middle buried; roots form in 10 to 15 days and the branch is cut free. (4) Tissue culture: many plantlets are grown from a few cells of a shoot tip on a nutrient medium in sterile conditions, giving virus-free banana plants and orchids in large numbers. Advantages: identical plants with desired qualities; quicker fruiting; plants that make few or no seeds (banana, sugarcane) can be grown. Disadvantage: no variation, so one disease can wipe out a whole crop.

Budding. A small outgrowth (bud) forms at one spot on the parent by repeated cell division, grows, and separates as a new individual. Yeast in warm sugar solution shows round buds on parent cells, sometimes in chains, under the microscope after 1 to 2 hours; in Hydra a bud grows on the body wall, develops tentacles and drops off.

Spore formation. In moist bread or roti kept warm (25 to 35 °C), dark and moist, fuzzy mould appears in about 3 days. Rhizopus shows thread-like hyphae with round sacs (sporangia) full of tiny spores; Aspergillus bears spores on a swollen tip. Spores are tiny, light, usually single-celled and made in huge numbers; they float in the air and germinate when they land on a moist, food-rich surface. The mould came from spores in the air, not from the bread itself; Louis Pasteur showed that life comes only from pre-existing life. Cold slows spore growth, which is why refrigeration keeps food fresh. Because these methods use mitosis, offspring are clones.

Counting growth. If a cell divides into 2 every fixed interval, the number after n intervals is the starting number × 2ⁿ; if each plantlet gives m new plantlets per cycle, the number after n cycles is the start × mⁿ.

Asexual Reproduction and Vegetative Propagation: formulas and key facts

Asexual versus sexual: Asexual: 1 parent, mitosis, clones | sexual: 2 parents, meiosis for gametes, variation
Doubling: $N u mb er a f t er n d o u b l in g s = s t a r t \times 2^{n}$
Multiplication per cycle: $N u mb er a f t er n cy c l es = s t a r t \times m^{n} (m = n e w pl an tl e t s f r o m e a c h p er cy c l e)$
Cutting depth: Bury about half the cutting's length at 45° to 60°
Spore growth conditions: Warm 25 to 35 °C
dark
moist
food available
mould visible in about 3 days

How to solve Asexual Reproduction and Vegetative Propagation questions

Use this method for questions on modes of asexual reproduction and growth numericals.

1Identify the mode from the clues: a plant part growing into a plant (vegetative), an outgrowth on a cell or body (budding), tiny airborne cells in sacs (spores).
2For artificial methods, name the method and the plant part used (stem cutting, scion and stock, bent branch, shoot-tip cells).
3Remember that all asexual offspring are clones made by mitosis and give one benefit and one risk.
4For growth numericals, count the number of doublings (time ÷ interval) and use start × 2ⁿ.
5For several cycles of multiplication, use start × mⁿ and solve for n by trying successive powers.
6Check by working backwards from the final number.

Asexual Reproduction and Vegetative Propagation 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.

Starting a money plant at home

Suppose a student cuts a 24 cm piece of money plant stem that has three nodes, removes its lower leaves, and plants it in damp soil in a pot.

How deep should it be buried, at what angle, and why does it grow into a plant identical to the parent?

Try it first, then show the solutionSolution

About half its length should be buried: 24 ÷ 2 = 12 cm, leaving 12 cm above the soil.
It should be planted at 45° to 60° and kept moist.
Roots and shoots grow from the nodes by mitosis; there are no gametes, so there is no mixing and the new plant is a clone of the parent.

Answer: 12 cm deep at 45° to 60°; a clone because it is made by mitosis from a vegetative part.

Memory hook: Half in, half out, damp and slanted.

Why bread goes mouldy in the box

Suppose a piece of roti is kept in a closed damp box in a warm cupboard, and after three days it is covered with fuzzy grey growth.

Explain where the mould came from and why the refrigerator would have slowed it.

Try it first, then show the solutionSolution

Tiny spores float in the air; some landed on the moist roti, which is rich in food.
The spores germinated into hyphae, forming a mycelium that makes new sporangia full of spores.
In a refrigerator the low temperature slows the growth of spores, so the food stays fresh longer.

Answer: From airborne spores; cold slows their growth.

Memory hook: Warm, dark and damp invites the spores.

Tricks to remember Asexual Reproduction and Vegetative Propagation

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

One parent, one copy
Asexual means one parent and offspring that are copies (clones) made by mitosis.
Use it when: Distinguishing asexual from sexual reproduction.
Scion goes on stock
Scion = the shoot you want to grow (the top); stock = the rooted plant it sits on (the bottom).
Use it when: Grafting questions.
Cut, graft, layer, culture
The four artificial methods: cutting, grafting, layering, tissue culture.
Use it when: Listing methods of vegetative propagation.
Bud, spore, piece
Budding (yeast, Hydra), spore formation (bread mould), vegetative piece (potato, Bryophyllum).
Use it when: Naming modes with examples.

Asexual Reproduction and Vegetative Propagation: solved examples

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

Example 1: Asexual versus sexual reproduction · 3 marks · Short answerBoard level

Give three differences between asexual and sexual reproduction and one example of each in plants.

Try it first, then show the solutionSolution

Number of parents: asexual one; sexual two (a male and a female gamete). (1)
Cell division and offspring: asexual by mitosis, offspring identical clones; sexual involves meiosis to make gametes and offspring show variation. (1)
Examples in plants: asexual: potato eyes, money plant cutting; sexual: seed formation in a pea or mango flower. Asexual is faster. (1)

Answer: Parents (1 or 2), mitosis versus meiosis with variation, speed; example potato cutting versus seed.

Example 2: Grafting and cutting · 3 marks · Short answerBoard level

(a) Define scion and stock. (1)
(b) Why do farmers graft a good mango variety on a hardy rooted plant? (1)
(c) Give one advantage and one disadvantage of vegetative propagation. (1)

Try it first, then show the solutionSolution

(a) The scion is the shoot of the desired variety; the stock is the rooted plant into whose slit it is fitted. (1)
(b) The graft gives plants with the desired fruit qualities that fruit sooner, using the strong roots of the stock. (1)
(c) Advantage: identical plants with desired qualities, and quicker fruiting. Disadvantage: no variation, so one disease can destroy the whole crop. (1)

Answer: (a) shoot and rooted plant; (b) desired fruit qualities with hardy roots; (c) identical plants versus no variation.

Example 3: Growth of a yeast culture by budding · 5 marks · Long answerHarder board level

A yeast culture starts with 50 cells in warm sugar solution. Assume each cell produces a bud that becomes a new cell every 90 minutes, so the number doubles every 90 minutes.
(a) How many cells are present after 6 hours? (1)
(b) How many after 9 hours? (1)
(c) After how many hours does the number first exceed 10 000? (2)
(d) Why are the new cells often seen in chains? (1)

Try it first, then show the solutionSolution

(a) 6 h = 360 min = 4 doublings. Cells = 50 × 2⁴ = 50 × 16 = 800. (1)
(b) 9 h = 540 min = 6 doublings. Cells = 50 × 2⁶ = 50 × 64 = 3200. (1)
(c) Need 50 × 2ⁿ > 10 000, so 2ⁿ > 200. 2⁷ = 128 is too small; 2⁸ = 256 works, giving 12 800 cells. Time = 8 × 1.5 h = 12 hours. (2)
(d) A new bud begins to bud before it separates, so cells stay attached in chains. (1)

Answer: (a) 800; (b) 3200; (c) 12 hours (12 800 cells); (d) buds start budding before separating.

Example 4: Tissue culture and clones · 5 marks · Long answerHarder board level

A tissue culture laboratory starts with one shoot tip. Each plantlet gives 5 new plantlets every 4 weeks.
(a) How many plantlets are there after 12 weeks? (1)
(b) After how many weeks is the number first more than 3000? (2)
(c) Why are these plantlets virus-free if the shoot tip was virus-free? (1)
(d) State one disadvantage of a field planted entirely with these plantlets. (1)

Try it first, then show the solutionSolution

(a) 12 weeks = 3 cycles; plantlets = 1 × 5³ = 125. (1)
(b) 5⁴ = 625 is too few; 5⁵ = 3125 is more than 3000, so 5 cycles = 5 × 4 = 20 weeks. (2)
(c) All plantlets come by mitosis from the same few virus-free cells in sterile conditions, so they carry no virus. (1)
(d) They are all genetically identical, so a single disease or pest that attacks one can destroy the whole field. (1)

Answer: (a) 125; (b) 20 weeks (3125); (c) virus-free cells copied by mitosis in sterile conditions; (d) no variation, so one disease can destroy all.

Example 5: Clones versus variation in an orchard · 4 marks · Case-basedHOTS / competency

Suppose a farmer plants 400 grafted trees, all cloned from one parent tree, and another farmer plants 400 seed-grown trees of the same fruit. A fungal disease arrives that kills every tree that lacks a particular resistance gene. The parent tree lacked it, and 5% of the seed-grown trees have it.
(a) How many trees of each orchard survive? (1)
(b) Explain why the results differ. (1)
(c) Give two reasons why the first farmer still chose grafting. (1)
(d) Name the process that produces variation in the seed-grown trees. (1)

Try it first, then show the solutionSolution

(a) Grafted orchard: 0 survive (all lack the gene). Seed-grown orchard: 5% of 400 = 20 survive. (1)
(b) Grafted trees are clones made by mitosis, so they are all equally susceptible; sexual reproduction gives variation, so a few seedlings are resistant. (1)
(c) Grafting gives trees with the desired fruit qualities and they fruit sooner than seedlings. (1)
(d) Sexual reproduction: meiosis forms gametes with different combinations of chromosomes, and fertilisation combines them. (1)

Answer: (a) 0 and 20; (b) clones are all susceptible; (c) quality and quicker fruiting; (d) meiosis and fertilisation.

Where students lose marks in Asexual Reproduction and Vegetative Propagation

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

Mistake: Saying asexual offspring are not exactly like the parent.
Plants from cuttings may look different if the soil differs.
Wrong working
Offspring have a mixture of both parents.
Right working
Asexual offspring are identical clones of the single parent, made by mitosis.
Do this: One parent: copies. Two parents: mixture.
Usually costs: 1 mark.
Mistake: Mixing up scion and stock.
Both names look similar.
Wrong working
Stock is the shoot of the desired variety.
Right working
The scion is the shoot of the desired variety; the stock is the rooted plant.
Do this: Stock = rooted base.
Usually costs: 1 mark.
Mistake: Writing that bread mould comes from the bread.
It appears to grow out of the bread.
Wrong working
Mould forms on its own from the bread.
Right working
Mould grows from spores that float in the air and land on the bread.
Do this: Recall Pasteur: life comes from pre-existing life.
Usually costs: 1 mark.
Mistake: Counting a doubling per hour when the interval is 90 minutes.
The time is not divided by the interval.
Wrong working
6 hours: 50 × 2⁶ = 3200
Right working
6 hours = 4 intervals: 50 × 2⁴ = 800
Do this: Divide time by interval first.
Usually costs: 2 marks.
Mistake: Naming only advantages of vegetative propagation.
The disadvantage is forgotten.
Wrong working
Vegetative propagation has no disadvantage.
Right working
It produces no variation, so a disease can destroy the whole crop.
Do this: Always add the risk of clones.
Usually costs: 1 mark.

Exam tips

Name the method, the plant part used and one example every time (cutting: stem of rose; grafting: mango; layering: jasmine).
Link 'clone' with 'mitosis' and 'one parent' in your explanation.
Draw budding in Hydra and yeast, and Rhizopus with sporangia, hyphae and spores labelled.
In growth numericals write the number of doublings explicitly.
End any propagation answer with the risk: no variation.

Practice questions on Asexual Reproduction and Vegetative Propagation

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
Define budding. Name one animal and one single-celled organism that reproduce by budding.
Hint
A bud grows at one spot and separates.
Answer
Budding is the formation of a small outgrowth (bud) by repeated cell division at one spot on the parent, which grows and separates as a new individual (1 mark). Hydra is the animal and yeast is the single-celled organism (1 mark).
Q2 · 3 marks · Short answerHarder board level
A gardener plants a rose cutting 20 cm long, and bends a jasmine branch to layer it on 5 October. (a) How deep should the cutting be buried, and at what angle? (b) Between which dates will the layered branch have roots and be ready to be cut free (10 to 15 days)?
Hint
Half the length; count days from 5 October.
Answer
(a) About half the length, 20 ÷ 2 = 10 cm, at 45° to 60° (1 mark). (b) 5 October + 10 days = 15 October; + 15 days = 20 October, so between 15 and 20 October (2 marks).
Q3 · 2 marks · Assertion-reasonBoard level
Assertion (A): Plants produced by vegetative propagation are genetically identical to the parent. Reason (R): They are formed by mitosis and no gametes are involved. 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
Mitosis copies the cell exactly.
Answer
(a). Mitosis produces genetically identical cells and there is no mixing of gametes, so the new plant is a clone.
Q4 · 3 marks · Short answerHarder board level
In the bread mould activity, a piece of moist bread is kept in a closed box at 30 °C. (a) Why is the box kept dark, warm and moist? (b) Where did the mould come from? (c) Name the structures that hold the spores in Rhizopus. (d) Why does a refrigerator keep bread fresh longer?
Hint
Spores need moisture, food and warmth.
Answer
(a) Warm, moist and dark conditions suit the germination and growth of the spores (1 mark). (b) From spores in the air that landed on the bread (not from the bread itself) (1 mark). (c) Sporangia, the round sacs on the hyphae; refrigeration slows spore growth (1 mark).
Q5 · 4 marks · Case-basedHOTS / competency
Banana plants produce few or no seeds and are grown from suckers and tissue culture. Bacteria divide by binary fission every 30 minutes. (a) Why can banana be grown by vegetative propagation? (b) How many bacteria arise from one after 5 hours? (c) State one risk of growing a whole plantation from a single clone. (d) Explain why sexual reproduction would give the plantation some protection from a new disease.
Hint
5 hours has 10 intervals of 30 minutes.
Answer
(a) A new plant grows from a vegetative part, so seeds are not needed (1 mark). (b) 5 hours = 10 divisions; 2¹⁰ = 1024 bacteria (1 mark). (c) A single disease can destroy the whole plantation because all the plants are identical (1 mark). (d) Sexual reproduction gives variation, so some plants may resist the disease (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.Name four artificial methods of vegetative propagation.Show answer
Cutting, grafting, layering and tissue culture.
2.Which plant forms plantlets on its leaf margins?Show answer
Bryophyllum.
3.What are the round sacs of Rhizopus called?Show answer
Sporangia, which contain the spores.
4.Which type of cell division makes asexual offspring?Show answer
Mitosis.
5.What does Pasteur's experiment show?Show answer
That life comes only from pre-existing life.
6.Which method gives virus-free banana plants?Show answer
Tissue culture.

Asexual Reproduction and Vegetative Propagation: frequently asked questions

Why do potatoes sprout in a dark cupboard?

The eyes on the potato are buds on an underground stem; with moisture and warmth they grow into new plants by vegetative propagation.

Is a plantlet from tissue culture the same as a seedling?

No. A seedling comes from a seed made by sexual reproduction and shows variation; a tissue-culture plantlet is a clone.

Why does refrigeration keep food fresh?

The cold slows the growth of mould and bacteria from spores and cells.

Do all fungi reproduce by spores?

Fungi commonly reproduce by spores; yeast, a single-celled fungus, reproduces by budding.

Why can grafted fruit trees fruit sooner than seedlings?

The scion is cut from a mature tree, so it carries its fruiting ability, and the stock supplies roots.