- Plant stems vary according to dicot and monocot.
- Stems show both primary & secondary growth.
- Primary growth is extension along a stem
- Tissues where this growth occurs are called primary meristems
- Secondary growth occurs as an increase in diameter of the stem
- Tissues where this occurs are called secondary meristems
Structure of the stem
External Structure of a Stem
Monocot Stems - Monocot Stems are characterized by Vascular Bundles evenly distributed throughout the ground tissue
- Vascular bundles are composed of both xylem & phloem and surrounded by a bundle sheath.
Monocot Stem
Dicot Stems
- Dicot stems are characterized by vascular bundles distributed radially around the stem perimeter
- Vascular bundles consist of a layered design
- Phloem tissue is located closest to the epidermis
- Vascular cambium (site of secondary growth) is located nearer the center
- Xylem tissue located nearest the center
- Woody Stems show similar tissue patterns.
- Develop a layer of bark outside the epidermis of the stem
- Develop annual rings which show growth of the tree over long periods of time.
No comments:
Post a Comment