Q.46 The swollen base of a petiole is known as
(A) Ligule (B) Hastule (C) Pulvinus (D) Stipule
Swollen Base of Petiole: Pulvinus in Plant Anatomy
The swollen base of a petiole is called a pulvinus, a specialized structure enabling leaf movements like nyctinasty in many plants.
Correct Answer
Answer: (C) Pulvinus
Pulvinus refers to the swollen, joint-like region at the petiole base, composed of flexible parenchyma cells that swell or shrink to move leaves, common in Fabaceae (legumes).
Botanical Definitions
Petiole is the leaf stalk connecting blade to stem; its swollen base forms a pulvinus for turgor-regulated movements.
This contrasts with other leaf base features, aiding in sleep movements (nyctinasty) or seismonasty, as in Mimosa.
Option Analysis
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(A) Ligule: Incorrect. Ligule is a membranous flap on grass leaves at blade-sheath junction, not a swollen petiole base.
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(B) Hastule: Incorrect. Hastule is the short stalk on coral polyps or leaf stalks in some contexts; unrelated to plant petiole swelling.
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(C) Pulvinus: Correct. Specifically denotes swollen petiole base facilitating movement via water changes.
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(D) Stipule: Incorrect. Stipules are paired, leaf-like appendages at petiole base, often protective, not swollen.
| Option | Definition | Relation to Swollen Petiole Base |
|---|---|---|
| (A) Ligule | Grass leaf membrane | None |
| (B) Hastule | Coral/leaf stalk | Not swollen |
| (C) Pulvinus | Swollen joint | Exact match |
| (D) Stipule | Paired appendages | Adjacent, not swollen |
Keywords: pulvinus, petiole base, leaf anatomy, botany MCQ, ligule stipule, plant morphology, Fabaceae pulvinus
