Anatomy Of Flowering Plants - Meristematic Tissue
Which meristem is responsible for increasing the girth of a woody dicot stem through secondary growth over successive years?
Select the correct option:
Solution
Lateral meristem
Plant growth depends on meristems, regions of actively dividing cells classified by NCERT according to their position and function. Lateral meristems, comprising the vascular cambium and cork cambium, lie along the sides of the axis and add cells in a radial direction, thereby increasing the girth or thickness of woody dicot stems and roots during secondary growth. The apical meristem is located at the tips of roots and shoots and is responsible for primary growth that increases length, not girth. The intercalary meristem occurs at the bases of internodes or leaves, especially in grasses, and contributes to elongation rather than thickening. Ground meristem is a primary meristematic tissue that differentiates into the cortex and pith but does not by itself drive yearly increases in girth. As stated in NCERT Class 11, Chapter 6 (Anatomy of Flowering Plants), lateral meristems are responsible for secondary growth. A developmental check confirms that radial addition of tissue producing wood and bark corresponds only to the lateral meristem.
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About This Question
- Subject
- biology
- Chapter
- structural organisation in animals and plants
- Topic
- anatomy of flowering plants - meristematic tissue
- Difficulty
- Medium
- Year
- 2025
Solution
Correct Answer:
Lateral meristem
Plant growth depends on meristems, regions of actively dividing cells classified by NCERT according to their position and function. Lateral meristems, comprising the vascular cambium and cork cambium, lie along the sides of the axis and add cells in a radial direction, thereby increasing the girth or thickness of woody dicot stems and roots during secondary growth. The apical meristem is located at the tips of roots and shoots and is responsible for primary growth that increases length, not girth. The intercalary meristem occurs at the bases of internodes or leaves, especially in grasses, and contributes to elongation rather than thickening. Ground meristem is a primary meristematic tissue that differentiates into the cortex and pith but does not by itself drive yearly increases in girth. As stated in NCERT Class 11, Chapter 6 (Anatomy of Flowering Plants), lateral meristems are responsible for secondary growth. A developmental check confirms that radial addition of tissue producing wood and bark corresponds only to the lateral meristem.
This medium difficulty biology question is from the chapter structural organisation in animals and plants, covering the topic of anatomy of flowering plants - meristematic tissue. It appeared in the 2025 exam.
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