NDA Biology · Plant Biology

Seed, Fruit and Embryo Development

The seed embryo has a radicle (becomes the root) and a plumule (becomes the shoot); a false fruit like apple develops from the thalamus; and the ovule's nucellus stores reserve food.

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Why this matters

4 PYQs, EASY–MODERATE. The reliable fact is the radicle → root / plumule → shoot pair from the germinating embryo. Two reproductive-structure facts round it out: apple is a FALSE fruit (from the thalamus, not the ovary), and a sunflower 'flower' is actually an inflorescence (many florets).

Concept 1 of 3: The seed embryo — radicle and plumule

Inside every seed is a tiny embryo with two growing tips. The radicle points down and becomes the root; the plumule points up and becomes the shoot. The cotyledon stores food to fuel that early growth. Remember: Radicle → Root (both start with R, both go down).

Definition

The parts of the seed embryo and what each becomes on germination:

Radicle — the embryonic root; emerges first and grows DOWN into the primary root.
Plumule — the embryonic shoot; grows UP into the stem and leaves.
Cotyledon — stores reserve food for the seedling.
Seed coat (testa) — the protective outer layer.

Worked example

During germination, one structure of the embryo emerges first and grows downward to anchor the seedling. Name it and what it becomes.

Practice this conceptself-check · 3 quick reps

The same idea in a real exam question:

NDA · Apr 2021 · Q94Easy

Example 1 · Plant Biology · Seed, Fruit and Embryo Development

During seed germination, the part of the embryo which grows into root is

Radicle = Root, Plumule = shoot

Don't swap them. The radicle grows into the root (down); the plumule grows into the shoot (up). 'Radicle → Root' shares the R. Cotyledon and epicotyl are distractors — cotyledon stores food.

Concept 2 of 3: True vs false fruit, and the inflorescence

A true fruit develops from the ovary. A FALSE fruit (pseudocarp) has its fleshy edible part come from some OTHER floral part — in apple, that's the thalamus (receptacle). Separately, what looks like one big 'flower' in a sunflower or marigold is really an inflorescence — a cluster of many tiny florets.

Definition

Two reproductive-structure facts:

False fruit (pseudocarp) — the fleshy part develops from a floral part OTHER than the ovary. In apple, the edible flesh comes from the thalamus (receptacle); the true fruit is the core.
Inflorescence — a cluster of many small flowers (florets) on a common axis. Sunflower and marigold (family Asteraceae) are inflorescences, not single flowers — the colourful 'flower' is a head of many florets.

Structure	What it is	Example
False fruit (apple)	Fleshy part from the thalamus, not the ovary	Apple, pear (pseudocarps) Apple's edible part = thalamus / receptacle (NDA 2026), not petal/sepal/stamen.
Inflorescence	A cluster of many florets on one axis	Sunflower, marigold (Asteraceae) The colourful sunflower/marigold 'flower' is an INFLORESCENCE (NDA 2017).

Apple flesh = thalamus (false fruit); sunflower head = inflorescence (many florets).

Practice this conceptself-check · 3 quick reps

The same idea in a real exam question:

NDA · Apr 2026 · Q96Moderate

Example 2 · Plant Biology · Seed, Fruit and Embryo Development

Which part of the plant or flower contributes in the form of false fruit like apple?

Apple flesh = thalamus, not petal/sepal/stamen

In the apple (a false fruit), the fleshy edible part develops from the thalamus (receptacle). Petal, sepal and stamen are distractors — they don't become the flesh.

Sunflower = inflorescence, not a single flower

Sunflower and marigold belong to the composite family; the showy 'flower' is an inflorescence of many small florets, not one flower.

Drill 1 more on true vs false fruit, and the inflorescence

Concept 3 of 3: Parts of the ovule — where reserve food is stored

The ovule is the structure inside the ovary that becomes the seed. It has several named parts, but for the exam the key one is the nucellus — the nutritive tissue that holds the reserve food for the developing embryo.

Definition

Parts of the ovule and their roles:

Nucellus — the central nutritive tissue (megasporangium); holds the reserve food for the embryo.
Integument — the outer protective covering (becomes the seed coat).
Funicle — the stalk attaching the ovule to the ovary wall.
Chalaza — the base of the ovule where integuments and nucellus meet.

Ovule part	Role
Nucellus	Nutritive tissue holding the reserve food The ovule part with reserve food = nucellus (NDA 2026).
Integument	Outer protective layer (→ seed coat)
Funicle	Stalk attaching the ovule
Chalaza	Base where integument meets the nucellus

Reserve food = nucellus; protection = integument; stalk = funicle.

Practice this conceptself-check · 3 quick reps

The same idea in a real exam question:

NDA · Apr 2026 · Q98Moderate

Example 3 · Plant Biology · Seed, Fruit and Embryo Development

Which one of the following parts of an ovule possesses reserve food?

Reserve food = nucellus (not integument or funicle)

The ovule part with the reserve food is the nucellus (the nutritive megasporangium). The integument protects, the funicle is the stalk, the chalaza is the base — none store the food.

Summary — formulas & gotchas at a glance

A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.

Reference tables (2)

True vs false fruit, and the inflorescence2 rows

Structure	What it is	Example
False fruit (apple)	Fleshy part from the thalamus, not the ovary	Apple, pear (pseudocarps) Apple's edible part = thalamus / receptacle (NDA 2026), not petal/sepal/stamen.
Inflorescence	A cluster of many florets on one axis	Sunflower, marigold (Asteraceae) The colourful sunflower/marigold 'flower' is an INFLORESCENCE (NDA 2017).

Apple flesh = thalamus (false fruit); sunflower head = inflorescence (many florets).

Parts of the ovule — where reserve food is stored4 rows

Ovule part	Role
Nucellus	Nutritive tissue holding the reserve food The ovule part with reserve food = nucellus (NDA 2026).
Integument	Outer protective layer (→ seed coat)
Funicle	Stalk attaching the ovule
Chalaza	Base where integument meets the nucellus

Reserve food = nucellus; protection = integument; stalk = funicle.

Watch out for (4)

Radicle = Root, Plumule = shoot
→ The seed embryo — radicle and plumule
Apple flesh = thalamus, not petal/sepal/stamen
→ True vs false fruit, and the inflorescence
Sunflower = inflorescence, not a single flower
→ True vs false fruit, and the inflorescence
Reserve food = nucellus (not integument or funicle)
→ Parts of the ovule — where reserve food is stored

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