10/09/2025
🌱 Shoot System (Above Ground)
The shoot system is primarily involved in photosynthesis and reproduction.
Structure Function
Apical meristem: Region of actively dividing cells at the tip of the shoot; responsible for primary growth (growth in length).
Node: The point on the stem where a leaf (and a bud) is attached.
Internode: The section of the stem between two nodes.
Axillary bud: A bud found in the axil (angle) between the stem and the petiole; can develop into a new branch or flower.
Petiole: The stalk that attaches the leaf blade to the stem.
Midrib: The main central vein of a leaf; part of the leaf's vascular transport system.
Margin: The edge or border of the leaf blade.
Dorsal/Ventral Dorsal: refers to the upper side of the leaf (often darker) and Ventral refers to the lower side (often lighter).
Proximal/Distal Proximal: refers to the part of an organ closest to the point of attachment (e.g., the base of a leaf blade); Distal refers to the part furthest away (e.g., the tip of the leaf blade).
🌳 Root System (Below Ground)
The root system is primarily involved in anchorage, absorption, and storage.
Structure Function
Primary root: The first root that emerges from a germinating seed (radicle); in the illustrated taproot system, it is the main, dominant root.
Secondary root: Also called lateral roots; these are branch roots that grow out sideways from the primary root, increasing the area for absorption.
Root hair: Microscopic, thin-walled extensions of root epidermal cells that dramatically increase the surface area for the absorption of water and minerals.
Root system: The collective term for all the roots of a plant.