23.3 Stems

Point on a stem where a leaf is attached

Node

Region between nodes on plant stems

Internode

Plant structure containing undeveloped tissue that can produce new stems and leaves

Bud

Plant stem structure that contains xylem and phloem tissue

Vascular Bundle

Parenchyma cells inside the ring of vascular tissue in dicot stems

Pith

the type of plant growth that occurs at the tips of roots and shoots

Primary Growth

Pattern of plant growth in which stems increase in width

Secondary Growth

Lateral meristematic tissue that produces vascular tissues and increases the thickness of the stem over time

Vascular Cambium

Lateral meristematic tissue that produces the outer covering of stems

Cork Cambium

Older xylem near the center of a woody stem that no longer conducts water

Heartwood

Area in plants that surrounds heartwood and is active in fluid transport

Sapwood

Tree structure that includes all tissues outside the vascular cambium, including phloem, the cork cambium, and cork

Bark

In general, stems have three important functions: They produce leaves, branches, and flowers; they hold leaves up to the sunlight; and they transport substances between roots and leaves.

Key Concept

In monocots, vascular bundles are scattered throughout the stem. In dicots and most gymnosperms, vascular bundles are arranged in a cylinder.

Key Concept

Primary growth of stems is produced by cell divisions in the apical meristem. It takes place in all seed plants.

Key Concept

In conifers and dicots, secondary growth takes place in lateral meristematic tissues called the vascular cambium and cork cambium.

Key Concept