movement of water through plants

• what are the three ways that water moves through a plant

  Apoplast

  Symplast

  vacuolar
• Describe the apoplast pathway

  water passes through the spaces of the cell walls and between cells. it does not pass through any plasma membranes into the cells. this means that water moves by mass flow rather than osmosis. also, dissolved mineral ions and salts can be carried with the water.
• Describe the symplast pathway.

  Water enters the cell cytoplasm through the plasma membrane, it can then pass through the plasmodesmata from one cell to the next.
• Describe the vacuolar pathway

  This is similar to the symplast pathway, except water is not confined to the cytoplasm of the cells. water in this pathway is able to enter and pass through the vacuole as well.
• what is water potential?

  The tendency of water molecules to move from one place to another.
• Water always moves from a region of high water potential to an area of low water potential.
• The water potential of pure water is 0.
• in a plant cell, the cytoplasm contains mineral ions and sugars, these reduce the water potential of the cytoplasm as there are fewer free water molecules available than in pure water. As a result, the water potential in all plant cells is always negative.
• What happens to a plant cell, in terms of water up take, if you place into pure water and why?

  The plant cell take up water. this is because the water potential inside the plant is less than the water it is submerged in. water molecules will move along the water potential gradient into the cell.
• Why does a plant cell not continue to absorb water until it bursts?

  It is because the cell ahs a strong cellulose wall. once the cell is full of water and is turgid, the water inside the cell begins to exert pressure onto the cell wall called the pressure potential- as the pressure potential builds, the influx of water is reduced.
• what occurs to a plant cell placed in a salt solution, and why?

  The plant cell will lose water via osmosis. this is because the water potential in the salt solution is lower than the plant cell's. Water will move down the concentration gradient, from the higher water potential in the cell into the lower water potential conditions salt solution.
• What happens when a plant cell begins to lose water?

  As water continues to drain out of the cell, the cytoplasm and vacuole shrink in size. The cytoplasm is no longer pushing against the cell wall and the cell is no longer turgid but flaccid instead. When the plasma membrane is no longer in contact with the cell wall- it is a condition called plasmolysis,