Plant Anatomy: Shoots and Stems

The Shoot System

• Develops from the plumule after embryo in the seed
• Grows above ground and consists of a stem bearing branches, leaves, flowers, and fruits

Types of Buds

• Vegetative buds: develop into leaves, branches, or other vegetative parts of the plant
• Reproductive or flower buds: develop into flowers or groups of flowers

Typical Stem Structure

• Has leaves at regular intervals (nodes) with buds at the axle of the leaf
• Has a terminal bud at the growing point
• Internodes are the lengths of stem between nodes
• Typically stands erect from the ground

Functions of Stems

• Connects the root system to the leaves and flowers of the shoot system
• Supports all parts of the shoot system, including branches, leaves, buds, flowers, and fruits
• Facilitates absorption of maximum sunlight through leaf arrangement
• Transports water and dissolved minerals and nutrients from roots to leaves
• Transports food (e.g., sugars) made in leaves to other parts of the plant where needed or stored

Transport in the Stem

• Network of tubes (xylem and phloem) transport water, food, and other substances throughout the plant
• Xylem: consists of xylem vessels, responsible for carrying water from roots through stem and veins in leaves
• Phloem: made of sieve tubes, responsible for carrying food made in leaves to other parts of the plant