water movement in plants in different solutions:

Question 1

What happens when plant cells are bathed in a hypotonic solution?

Answer 1

Water enters the plant cells, raising the pressure potential and making the solute potential less negative, until the water potential of the plant tissue equals that of the bathing solution. If the solution is pure water, the cells become fully turgid.

Question 2

What is the effect of pure water on plant cells?

Answer 2

When plant cells are bathed in pure water (water potential = 0), the cells become turgid. The solute potential and pressure potential of the cells are equal but opposite in sign, balancing each other out at zero water potential.

Question 3

What happens when plant cells are bathed in a hypertonic solution?

Answer 3

In a hypertonic solution, water moves out of the plant cells, causing the pressure potential to drop. The cells become flaccid, and if water continues to leave, the cells plasmolyse (the plasma membrane detaches from the cell wall).

Question 4

Why does plasmolysis occur in hypertonic solutions?

Answer 4

Plasmolysis occurs because the solute potential of the bathing solution is more negative than that of the plant cells. This causes water to leave the cells, leading to a reduction in pressure potential and eventual plasmolysis when the cytoplasm shrinks away from the cell wall.

Question 5

What happens when water potential in plant cells equals that of the bathing solution?

Answer 5

When the water potential of plant cells equals that of the bathing solution, net movement of water stops, and the cells reach a state of equilibrium.