Modifications of Stem
Examination of stems modified for food storage (underground stems), support (tendrils), protection (thorns), and vegetative propagation.
What is Modifications of Stem?
An underground stem that grows horizontally, often thickened for food storage and bearing scale leaves, buds, and roots.
Key points
- Identify different types of stem modifications.
- Explain the function of each modified stem.
- Provide examples of plants exhibiting specific stem modifications.
- Differentiate between stem modifications and root modifications.
Common exam trap
Confusing modified stems with modified roots (e.g., sweet potato is a root tuber, potato is a stem tuber).
Definitions
- Term
Rhizome
- Meaning
An underground stem that grows horizontally, often thickened for food storage and bearing scale leaves, buds, and roots.
- Term
Corm
- Meaning
A short, vertical, swollen underground plant stem that serves as a storage organ, typically with scale leaves and buds.
- Term
Tuber
- Meaning
A swollen underground stem or root part, typically containing stored food, from which new plants can grow.
- Term
Tendril
- Meaning
A slender, coiling plant organ that arises from a leaf axil or stem tip, used for support and climbing.
- Term
Thorn
- Meaning
A sharp, pointed woody structure on a stem, often a modified axillary bud, serving as protection.
- Term
Phylloclade (Cladode)
- Meaning
A flattened or cylindrical stem that resembles and functions as a leaf, performing photosynthesis.
Learning objectives
Identify different types of stem modifications.
Explain the function of each modified stem.
Provide examples of plants exhibiting specific stem modifications.
Differentiate between stem modifications and root modifications.
Prerequisites
Basic knowledge of plant anatomy (stem structure, nodes, internodes, axillary buds).
Understanding of plant functions (support, conduction, storage, propagation).
Common mistakes
Confusing modified stems with modified roots (e.g., sweet potato is a root tuber, potato is a stem tuber).
Misidentifying the type of modification (e.g., calling a thorn a prickle).
Not recognizing the specific plant examples for each modification.
Keywords
Stem modification
Rhizome
Corm
Tuber
Tendril
Thorn
Phylloclade
Vegetative propagation
Underground stem
Aerial stem
Food storage
Support
Protection
Practice preview
Which of the following is a modification of the stem for food storage?…
easy
Which of the following statements about stem modifications is INCORRECT?…
medium
Consider the following examples of stem modifications: (i) Potato (Tuber), (ii) Ginger (Rhizome), (iii) Colocasia (Corm), (iv) Onion (Bulb). Which of these are primarily modified for food storage and also facilitate vege…
hard