The Xylem (OCR A Level Biology): Revision Note

Xylem Vessel Elements: Structure & Function

• The functions of xylem tissue in a plant are:

  • Vascular tissue that transports dissolved minerals and water around the plant

  • Structural support

  • Food storage

• Xylem tissue is made up of four cell types that function together:

1. Tracheids (long, narrow tapered cells with pits)

2. Vessel elements (large with thickened cell walls and no end plates when mature)

3. Xylem parenchyma

4. Sclerenchyma cells (fibres and sclereids)

• Most of the xylem tissue is made up of tracheids and vessel elements, which are both types of water-conducting cell

Xylem Diagram

Images of xylem vessel elements, (a) photomicrograph in longitudinal section (lignin is stained red), (b) scanning electron micrograph in transverse section and (c) microscope image in transverse section and drawing (lignin is stained red)

Relating Structure & Function in Xylem Vessel Elements Table

• Also see Comparison of xylem & phloem tissue table in Phloem Sieve Tube Elements