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Sweet Potato vs Potato: Modified Root or Modified Stem?

Biology · Morphology of Flowering Plants · NEET

Sweet potato is a modified adventitious ROOT (a tuberous root that stores food). Potato is a modified underground STEM called a stem tuber. Memory hook: potato has "eyes" (buds on nodes) so it is a STEM; sweet potato has no eyes, so it is a ROOT.
Same look, different organ: check for eyes (buds)POTATO = modified STEMeyeEyes = nodes + buds → STEM tuberSWEET POTATO = modified ROOTsmooth, no eyesNo eyes/nodes → adventitious ROOT
Potato (left) shows eyes, which are nodes with buds, so it is a modified underground stem tuber. Sweet potato (right) is smooth with no eyes, so it is a modified adventitious storage root. The presence or absence of eyes is the quickest NEET test.

Your doubts, answered

Is sweet potato a root or a stem?

Sweet potato is a modified ROOT. It is a tuberous adventitious root that swells to store food. It grows from the sides of the stem (adventitious), not from the radicle, so it is not a tap root either. It has no nodes, no buds and no eyes, which is why it is a root and not a stem.

Why is potato a stem and not a root?

Potato is an underground STEM tuber. It carries the true signs of a stem: nodes, internodes and axillary buds. The small pits you see, called eyes, are nodes bearing buds that can grow into new shoots. Roots never have nodes or buds, so potato must be a stem.

Is sweet potato a modified tap root or adventitious root?

Sweet potato is a modified ADVENTITIOUS root, not a tap root. A tap root grows straight down from the radicle. Sweet potato roots arise from the base of the stem, so they are adventitious. NEET 2018 tested exactly this and the answer was adventitious root, not tap root.

What is the difference between potato and sweet potato modification?

Potato = modified underground STEM (stem tuber) with eyes/nodes/buds. Sweet potato = modified ADVENTITIOUS ROOT (tuberous root) with no eyes. Both store food and both look swollen, but one is stem and the other is root. Do not group them together.

Are the eyes on a potato proof that it is a stem?

Yes. Each eye is a node with an axillary bud. Buds and nodes are stem features only, never root features. This is why a cut piece of potato with an eye can grow a whole new plant. No true root can do this from a bud.

Is sweet potato a tuber like potato?

They are different kinds of tuber. Potato is a STEM tuber (swollen stem tip). Sweet potato is a ROOT tuber / tuberous root (swollen adventitious root). The word 'tuber' alone in NCERT and NEET usually means the stem tuber of potato.

⚠️ The NEET trap
✗ Sweet potato is a modified tap root (because it stores food like carrot).
✓ Sweet potato is a modified ADVENTITIOUS root. It grows from the stem base, not from the radicle, so it cannot be a tap root.
🧠 NEET 2018 gave 'Tap root' as a trap option. Storage does not mean tap root. Ask: does it come from the radicle? If not, it is adventitious.

Real NEET questions

2018

Sweet potato is a modified:

A · Tap root
B · Adventitious root ✓
C · Stem
D · Rhizome
Solution: Sweet potato is a tuberous ADVENTITIOUS root modified for storage of food. It arises from the base of the stem, not from the radicle, so it is not a tap root. It has no nodes or buds, so it is not a stem or a rhizome. Correct answer: adventitious root.

Solved Morphology of Flowering Plants NEET PYQs

Try the real previous-year questions from this chapter — each with the answer and a full solution.

See all 46 Morphology of Flowering Plants NEET PYQs ›
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Frequently asked

Which one has eyes, potato or sweet potato?

Potato has eyes. Each eye is a node with a bud, proving potato is a stem. Sweet potato has no eyes, proving it is a root.

Is potato a rhizome?

No. Potato is a stem TUBER, not a rhizome. A rhizome (like ginger) grows horizontally underground; a stem tuber is the swollen tip of an underground branch that stores food.

Does sweet potato store food in stem or root?

In the root. Sweet potato stores food in swollen adventitious roots. Potato, in contrast, stores food in an underground stem.

What is the fastest one-line trick for the exam?

Potato = eyes = nodes = STEM. Sweet potato = no eyes = ROOT (adventitious). This single line answers most NEET questions on the pair.

Are carrot and sweet potato the same kind of root?

No. Carrot is a modified TAP root (from the radicle). Sweet potato is a modified ADVENTITIOUS root (from the stem base). Both store food but they differ in origin.

Related concepts:
Modifications of Root: Storage, Support & Respiratory RootsTap Root vs Fibrous Root vs Adventitious Root (with examples)Modifications of Stem: Underground, Aerial and Sub-aerialHow to Distinguish a Stem from a RootThe Stem: Nodes, Internodes and Buds Explained
Practise Biology for NEET:
Biology MCQs (free, chapter-wise)Morphology of Flowering Plants PYQs