3. movement of water through plants

When plant cells touch, water molecukes can pass between them. They always move from the cell with the higher water potential to the cell with the lower water potential.

3 possible pathways:

• Apoplast pathway (cell wall)
• symplast pathway (cytoplasm)
• vacuolar pathway (vacuole)

• moves through cell walls (water filled space between cellulose molecules)
• Does not pass through any plasma membranes
• permits passage of dissolved minerals and salts.

Water continues along the apoplast route until it reaches the casparian *****, in the endodermis.

The casparian ***** consists of the waxy substance, suberin. Once it hits this *****, it enters the cytoplasm of the endodermis and takes the symplast route.

• water enters through the plasma membrane into cell cytoplasm.
• It passes through the plasmodesmata (gaps in the cell wall).

• Travels through the cytoplasm and vacuoles.

• As the cell fills up, the water exerts turgor pressure on the cell wall, which is known as pressure potential.
• pressure increases = reduces water intake.