Xylem Structure
Biology: IB Diploma Higher Level, topic 7.2.5
Xylem Structure
The xylem are plant vessels that are responsible for transporting water and mineral ions. The structure of the xylem is specialised for this role.
Vessel elements
- The xylem vessels are long, tubes of cells that run up the stem of plants.
- The cells of the xylem are called vessel elements.
- The vessel elements in the xylem are dead.
End walls
- The vessel elements are stacked on top one another.
- There are no cell walls at the ends of each vessel element.
- This creates a continuous tube for water to flow through.
Lignin
- The walls of the xylem are lined with a waterproof polymer called lignin.
- Lignin reinforces the walls of the vessel elements to provide structural support.
Test yourself on Xylem Structure
Which of the following statements about the xylem structure are true?
Which of these is NOT a structural feature of xylem vessels?