Q.39 A typical floral meristem differs from shoot apical meristem on the basis of
(A) Determinate growth
(B) Presence of auxin
(C) Presence of stem cells
(D) Negative geotropism
The correct answer is (A) Determinate growth. Floral meristems exhibit determinate growth, producing a fixed number of floral organs before terminating, unlike the shoot apical meristem’s indeterminate growth.
Option Analysis
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(A) Determinate growth: Floral meristems have limited divisions, forming sepals, petals, stamens, and carpels then exhausting stem cells, while shoot apical meristems (SAM) continue producing leaves and stems indefinitely.
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(B) Presence of auxin: Both meristems rely on auxin for organ initiation and maintenance; auxin gradients regulate primordia in SAM and floral meristems equally.
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(C) Presence of stem cells: Stem cells exist in both, maintained by WUS-CLV pathways; floral meristems terminate them after organ formation.
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(D) Negative geotropism: SAM shows negative geotropism as shoots grow upward, but floral meristems form on shoots without distinct tropic differences.
The floral meristem differs from the shoot apical meristem primarily in growth patterns, crucial for CSIR NET Life Sciences preparation. Understanding these distinctions aids in mastering plant developmental biology.
Core Difference
Floral meristems show determinate growth, producing a set number of organs like sepals and carpels before stopping, unlike the endless vegetative growth of shoot apical meristems. This transition ensures reproductive success.
Growth Patterns
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Shoot apical meristem: Indeterminate, forms leaves, stems continuously.
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Floral meristem: Determinate, terminates post-organ formation via AGAMOUS gene repression of WUS.
Shared Features
Both maintain stem cells via WUS-CLV and use auxin for primordia positioning. Negative geotropism applies to shoots, not uniquely to floral meristems.
Exam Relevance
For CSIR NET, recognize determinate growth as the key differentiator in such MCQs.
