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Seed Structure and Germination ICSE Class 9 Biology Notes

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BiologyICSE Class 9 · Seeds: Structure and Germination

Seed Structure, Types and Germination Conditions (ICSE Class 9 Biology)

Updated 17 October 2026 · Fact-checked

A seed has a protective coat, an embryo (radicle, plumule and cotyledons) and stored food. A bean is a dicot seed (two cotyledons, endospermless) and maize is a monocot grain (one cotyledon, with endosperm). In epigeal germination the cotyledons come above the ground and in hypogeal they stay below; water, oxygen and a suitable temperature are required.

Notice the bean has two large cotyledons and no endosperm, while maize has one small cotyledon beside a big endosperm.

Illustration drawn for QuestionBuddy.

Understand Seed Structure, Types and Germination Conditions

1. Bean seed (dicot). Outer *testa* and inner *tegmen*; a scar (*hilum*) and a tiny pore (*micropyle*). Inside are two fleshy *cotyledons* holding food and an embryonic axis: the *plumule* (future shoot) and *radicle* (future root). No separate endosperm in the mature seed (non-endospermic).

2. Maize grain (monocot). The fruit wall and seed coat are fused. A single *cotyledon* (scutellum) lies beside a large *endosperm* that stores starch; the embryo has a plumule covered by *coleoptile* and a radicle covered by *coleorhiza*. Aleurone layer surrounds the endosperm.

3. Dicot versus monocot seed. Dicot: two cotyledons, usually no endosperm (bean, pea, gram); monocot: one cotyledon, endosperm present (maize, wheat, rice).

4. Germination. The seed absorbs water and swells; the radicle emerges and forms the root, the plumule forms the shoot.

  • *Epigeal*: the hypocotyl elongates and brings cotyledons above ground, as in bean and castor.
  • *Hypogeal*: the epicotyl elongates and cotyledons remain in the soil, as in pea and maize.

5. Conditions for germination. Water (activates enzymes and softens the coat), oxygen (for respiration), and a suitable temperature (about 25 to 35 degrees C). Light is usually not needed. Seeds also must be viable and, in some cases, must have ended dormancy.

6. Experiments. Four tubes: with water, without water, without oxygen (boiled water with oil layer) and at low temperature; only the tube with all three conditions shows germination.

Seed Structure, Types and Germination Conditions: key facts

Bean seed
  • Testa and tegmen
  • Hilum
  • Micropyle
  • Two cotyledons
  • Plumule
  • Radicle
Maize grain
  • One cotyledon
  • Endosperm
  • Coleoptile
  • Coleorhiza
  • Fruit and seed fused
Types of germination
Epigeal: cotyledons above ground, bean | Hypogeal: below ground, pea and maize
Conditions
  • Water
  • Oxygen
  • Suitable temperature
  • Viable seed

Seed Structure, Types and Germination Conditions in real life

The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Seeds in the kitchen

Suppose a student soaks a handful of chickpeas overnight and sees them swollen with a tiny root next morning, while dry ones are unchanged.

Explain the change.

Try it first, then show the solutionSolution
  1. Soaking supplies water, which the seed absorbs.
  2. Enzymes become active, the radicle grows out.
  3. Dry seeds cannot germinate without water.

Answer: Water starts germination.

Memory hook: Soak to sprout.

Tricks to remember Seed Structure, Types and Germination Conditions

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

  • Plumule = Plant above

    Plumule becomes shoot; radicle becomes root.

    Use it when: Seed parts.

  • Epi up, hypo hides

    Epigeal: cotyledons up; hypogeal: cotyledons stay.

    Use it when: Germination types.

Seed Structure, Types and Germination Conditions: solved examples

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

Example 1: Seed parts · 3 marks · Short answerBoard level

Name the part of the bean seed that (a) becomes the root, (b) stores food, (c) lets water enter. [3]

Try it first, then show the solutionSolution
  1. (a) Radicle.
  2. (b) Cotyledons.
  3. (c) Micropyle.

Answer: (a) Radicle (b) Cotyledons (c) Micropyle.

Example 2: Monocot vs dicot · 3 marks · Short answerHarder board level

A student sees a dry seed with two large fleshy halves and no extra food store beside the embryo, and another with one thin scale and a large starchy mass. Identify each and give three differences. [3]

Try it first, then show the solutionSolution
  1. Cotyledons: two versus one.
  2. Endosperm: absent versus present.
  3. Coverings: seed coat only versus fruit wall fused with seed coat.

Answer: The first is a dicot (bean): two cotyledons, no endosperm; the second is a monocot (maize): one cotyledon, large endosperm, fruit wall fused with seed coat.

Example 3: Germination experiment · 4 marks · Long answerHarder board level

Explain how you would show that oxygen is required for germination. [4]

Try it first, then show the solutionSolution
  1. Place soaked seeds in two flasks.
  2. One has boiled and cooled water with a layer of oil so that air cannot dissolve; the other has ordinary water with air.
  3. Keep both at the same temperature.
  4. Only the second shows germination; hence oxygen is needed.

Answer: Seeds in oxygen-free water do not germinate but those with air do.

Example 4: Epigeal reasoning · 3 marks · Short answerHarder board level

Why must the seedlings of epigeal germination be planted shallow? [3]

Try it first, then show the solutionSolution
  1. The hypocotyl lifts the cotyledons out of the soil.
  2. Deep planting makes the shoot long before it reaches the light.
  3. The seedling may exhaust its stored food.

Answer: Cotyledons need to reach the surface.

Example 5: Case: the failed sowing · 6 marks · Case-basedHOTS / competency

Case. A farmer sowed bean seeds in cold, dry soil and none germinated. (i) Name two missing conditions. [2] (ii) State one process that failed to start. [1] (iii) Suggest a remedy. [2] (iv) Why is light not required? [1]

Try it first, then show the solutionSolution
  1. (i) Water and a suitable temperature.
  2. (ii) Enzyme activity or respiration.
  3. (iii) Irrigate and sow in the right season.
  4. (iv) Germination uses stored food, not photosynthesis.

Answer: (i) Water and warmth (ii) Enzyme activation (iii) Water and warm season (iv) Food is already stored.

Where students lose marks in Seed Structure, Types and Germination Conditions

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

  • Mistake: Confusing plumule and radicle

    Direction of growth is ignored.

    Do this: Plumule up, radicle down.

    Usually costs: 1 mark.

  • Mistake: Saying light is required

    Misconception.

    Do this: Light is not required for germination.

    Usually costs: 1 mark.

  • Mistake: Calling all seeds endospermic

    Bean has none.

    Do this: State monocot/dicot difference.

    Usually costs: 1 mark.

Exam tips

  • Draw labelled diagrams of both bean and maize.
  • Link the structure to the function.
  • State controls in experiments.
  • Mention examples for both types of germination.

Practice questions on Seed Structure, Types and Germination Conditions

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

  1. Q1 · 1 mark · MCQBoard level

    The scutellum of the maize grain is the:
    (a) endosperm
    (b) cotyledon
    (c) plumule
    (d) radicle

    Hint

    Single cotyledon.

    Answer

    (b) cotyledon.

  2. Q2 · 2 marks · Very short answerBoard level

    Name the two parts of the embryonic axis. [2]

    Hint

    Shoot and root.

    Answer

    Plumule and radicle.

  3. Q3 · 2 marks · Very short answerBoard level

    What is the difference between the hilum and the micropyle? [2]

    Hint

    Scar and pore.

    Answer

    The hilum is the scar where the seed was attached; the micropyle is a tiny pore for water entry.

  4. Q4 · 1 mark · Assertion-reasonHarder board level

    Assertion (A): Seeds do not need light to germinate.
    Reason (R): The embryo uses stored food for early growth.
    (a) Both A and R are true and R is the correct explanation of A.
    (b) Both A and R are true but R is not the correct explanation of A.
    (c) A is true but R is false.
    (d) A is false but R is true.

    Hint

    Food.

    Answer

    (a).

  5. Q5 · 3 marks · Short answerHarder board level

    Describe how a pea seed germinates hypogeally. [3]

    Hint

    Epicotyl.

    Answer

    Water is absorbed, the radicle emerges, and the epicotyl elongates; the cotyledons remain in the soil.

  6. Q6 · 2 marks · Very short answerBoard level

    Why does a seed swell when soaked? State two changes. [2]

    Hint

    Imbibition.

    Answer

    It absorbs water and swells, softening the seed coat and activating enzymes.

  7. Q7 · 3 marks · Short answerHarder board level

    Compare epigeal and hypogeal germination with an example of each. [3]

    Hint

    Position.

    Answer

    Epigeal: cotyledons come above ground, as in bean; hypogeal: they stay below, as in pea.

  8. Q8 · 3 marks · Short answerHarder board level

    Seeds of a plant are stored in a sealed dry jar for a year and then sown. Name conditions that must be supplied to start germination, and explain dormancy. [3]

    Hint

    Rest.

    Answer

    Water, oxygen and a suitable temperature; dormancy is a resting period in which the seed does not germinate even if conditions are given.

  9. Q9 · 4 marks · Case-basedHOTS / competency

    Case. A student cuts a soaked bean open and an iodine drop turns the cotyledon blue-black while a maize grain colours its endosperm. (i) What does the colour show? [1] (ii) Where is food stored in each? [2] (iii) Why does this matter to the young plant? [1]

    Hint

    Starch.

    Answer

    (i) Starch. (ii) Bean: cotyledons; maize: endosperm. (iii) It supplies food for the early seedling.

  10. Q10 · 3 marks · Long answerHOTS / competency

    Case. A seed tray is kept near a heater and the seeds dry out and fail to germinate though kept warm. Explain which condition was missing and the effect of excess heat. [3]

    Hint

    Balance.

    Answer

    Water was missing because heat dried the tray; too much heat can also damage enzymes and kill the embryo.

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. 1.Embryonic root?Show answer

    Radicle.

  2. 2.Cotyledons in maize?Show answer

    One.

  3. 3.Hypogeal example?Show answer

    Pea.

  4. 4.Conditions for germination?Show answer

    Water, oxygen, suitable temperature.

  5. 5.Food store in maize?Show answer

    Endosperm.

Seed Structure, Types and Germination Conditions: frequently asked questions

Is the coleoptile a leaf?

It is a protective sheath around the plumule.

Why boil the water?

To remove dissolved oxygen.

What is viability?

The ability of a seed to germinate.