Pathway Taken by Water (Cambridge International IGCSE Biology)

Spec point — 8.1.3 · Outline the pathway taken by water through the root, stem and leaf as: root hair cells, root cortex cells, xylem, mesophyll cells

Pathway taken by water

• Water is taken up from the soil into root hair cells
• Water then moves across the root cortex and into the xylem vessels by osmosis

Pathway of water into and across a root

• Water is then transported in the xylem to the leaves where it enters the leaf mesophyll cells
• So the pathway is:

root hair cell → root cortex cells → xylem → leaf mesophyll cells

Investigating Water Movement in Plants

Spec point — 8.1.3 · Investigate, using a suitable stain, the pathway of water through the above-ground parts of a plant

• The pathway taken by water through a plant can be studied using a suitable stain, or dye, as follows:

  • place a plant stem, e.g. celery, into a beaker of water that has had a stain added to it
  • leave for a few hours, or until the leaves of the celery turn the same colour as the dyed water (indicating that the dye has travelled all the way up the xylem)
  • cut a cross-section of the stem and view the position of the coloured dye, which will correspond with the location of the xylem vessels

It is possible to study the pathway taken by water in a plant stem using a suitable stain