Secondary growth

Definition

Secondary growth is the increase in thickness or girth of plant stems and roots due to the activity of the vascular cambium and cork cambium. This process allows plants to strengthen their structures and support larger leaves and branches.

5 Must Know Facts For Your Next Test

1. Secondary growth occurs primarily in dicotyledons and gymnosperms.
2. The vascular cambium produces secondary xylem (wood) on the inside and secondary phloem on the outside.
3. Cork cambium generates cork cells that form part of the protective outer layer known as bark.
4. Annual rings in trees are a result of seasonal variations in secondary xylem production.
5. Secondary growth enables older stems to continue transporting water and nutrients efficiently.

Review Questions

• What plant tissues are responsible for secondary growth?
• How do annual rings form during secondary growth?
• Why is secondary growth important for plants?

Related terms

vascularCambium: A cylindrical layer of meristematic tissue in plants that produces secondary xylem and phloem.

corkCambium: A lateral meristem that forms the periderm, replacing the epidermis in roots and stems during secondary growth.

primaryGrowth: The elongation of plant stems and roots through apical meristems, leading to increased height or length rather than thickness.