Pathway Taken by Water (Cambridge (CIE) O Level Biology): Revision Note

Pathway Taken by Water

• Water enters roots via root hair cells, by the process of osmosis

• Water then moves across the root, through the cells of the root cortex

• Water travels from the roots to the leaves of plants in the xylem, where it moves into the cells of the leaf mesophyll

• The pathway of water through a plant can be summarised as follows:

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

Water movement across plant roots diagram

Water enters roots via the roots hair cells and crosses the cortex to reach the xylem

Water movement through a leaf diagram

Water exits the xylem in the leaves, where it enters the mesophyll cells before being lost through the stomata

Investigating Water Movement in Plants

• The movement of water through a plant can be observed by placing a plant stem, e.g. celery, into a beaker of water that has had a stain added to it, e.g. food colouring

• The dyed water will be taken up by the celery, and travel through the xylem to the leaves

• A cross-section cut through the celery stem will show regions of different colour from the food dye; this shows the location of the xylem vessels

Water movement in celery diagram

Food colouring can be used to show the location of xylem vessels in celery stems