Question

How does water move within the root?

Answer 1

Movement of water in roots:
Water and mineral solutes are absorbed by the root hairs by osmosis. After water is absorbed by the root hairs, it goes into the xylem by two distinct pathways:

1. apoplastic pathway
2. symplastic pathway

Apoplastic pathway:

1. The apoplastic pathway includes interconnected cell walls which are continuous throughout the plant excluding the casparian strips of the endodermis in the roots.
2. The movement of water occurs through the intercellular spaces and the cell walls.
3. The water does not cross the cell membrane or enter the cytoplasm.

Symplast pathway:

1. The symplast pathway is when the water enters the cytoplasm and goes from one cell to another through the plasmodesmata.
2. This route of water is taken when it reaches the endodermis of the root.

Casparian strip:

1. The endodermal cells have suberin in their cell walls that are impermeable to water.
2. This blocks the movement of water and minerals through the cell wall route.
3. Thus the water moves in cortical cells through apoplast but it moves through the endodermis by symplast.