Bark

Definition

Bark is the outermost layers of stems and roots in woody plants. It protects the plant from physical damage and pathogens while also aiding in nutrient transport.

5 Must Know Facts For Your Next Test

1. Bark consists of two main layers: the outer bark (periderm) and the inner bark (phloem).
2. The periderm includes cork cells, which are dead at maturity and provide a protective barrier.
3. Phloem, part of the inner bark, is responsible for transporting nutrients like sugars throughout the plant.
4. Bark can vary greatly among different species in texture, thickness, and appearance.
5. Secondary growth in woody plants leads to the continuous production and shedding of bark.

Review Questions

• What are the two main layers that make up bark?
• How does bark contribute to a plant's defense mechanisms?
• What role does phloem play within the inner layer of bark?

Related terms

Xylem: The vascular tissue responsible for transporting water and dissolved minerals from roots to other parts of the plant.

Cambium: A layer of actively dividing cells between xylem and phloem that contributes to secondary growth.

Periderm: A protective tissue that replaces epidermis during secondary growth in stems and roots.