Pathway Taken by Water

• Osmosis causes water to pass into the root hair cells, through the root cortex and into the xylem vessels:

  
  

• Once the water gets into the xylem, it is carried up to the leaves where it enters mesophyll cells

• So the pathway is:

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

Investigating Water Movement in Plants

• The pathway can be investigated by placing a plant (like celery) into a beaker of water that has had a stain added to it (food colouring will work well)

• After a few hours, you can see the leaves of the celery turning the same colour as the dyed water, proving that water is being taken up by the celery

• If a cross-section of the celery is cut, only certain areas of the stalk is stained the colour of the water, showing that the water is being carried in specific vessels through the stem - these are the xylem vessels

Ways

• Water enters plants primarily through root hairs and moves through the cortex and endodermis before reaching the vascular cylinder, where it enters the xylem for transport.

• Water can move through the plant via two main pathways: the apoplast pathway (outside the cell membranes) and the symplast pathway (through the cytoplasm), which help in efficient nutrient transport.

• Apoplast Pathway means by which water and solutes move through the spaces outside of plant cells, primarily via cell walls and intercellular spaces. This transport method bypasses the plasma membranes and is crucial for delivering materials to the xylem.

• In the symplastic pathway, the movement of water is in between the cytoplasm and the vacuoles through the plasma membranes and plasmodesmata and beyond the cortex of plant cells.