Q.33 Vascular bundles in monocot plants are
Vascular bundles in monocot plants are closed and scattered throughout the ground tissue (stele), making option (4) correct.
Question Breakdown
This tests stem anatomy in monocots (e.g., maize, rice), where vascular bundles (xylem + phloem) lack cambium and are distributed randomly, unlike dicots’ ring arrangement.
Option Analysis
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(1) Arranged in rings: Incorrect; describes dicot stems (eustele), enabling secondary growth via cambium rings.
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(2) Arranged in stele region: Incorrect; too vague—stele is ground tissue enclosing vascular elements, but doesn’t specify monocot pattern.
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(3) Scattered in stele region: Partially correct on scattering but omits “closed” (no cambium), making it incomplete.
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(4) Closed and scattered in stele region: Correct; monocot bundles are conjoint, collateral, closed (absent cambium), scattered in stem ground tissue.
Vascular bundles monocot plants feature a closed and scattered arrangement in the stele region, vital for GATE Life Sciences anatomy questions on plant stems. Without cambium, monocots show no secondary thickening, with bundles embedded randomly in ground tissue for efficient transport.
Monocot Stem Anatomy
Each vascular bundle contains xylem (inner, endarch) and phloem (outer), surrounded by sclerenchymatous sheath. Scattered distribution (~50-100 bundles) contrasts dicot ring pattern.
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Closed: No intrafascicular cambium.
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Scattered: Throughout pith/ground tissue, no distinct cortex/pith.
Comparison Table
| Feature | Monocot Stem | Dicot Stem |
|---|---|---|
| Arrangement | Closed, scattered | Open, ring (eustele) |
| Cambium | Absent | Present between xylem/phloem |
| Secondary Growth | None | Occurs |
| Examples | Maize, bamboo | Sunflower, pea |
Exam Tips
GATE traps option (3) by omitting “closed.” Visualize: Monocot T.S. shows dots (bundles) vs. dicot wheel-spoke. Key for monocot-dicot differentiation MCQs.
