How do plant cells shrink by osmosis

If a plant cell has a cell wall which keeps it turgid and allows it to stay strong, how does the cell shrink and wilt when water leaves the cell by osmosis? The cell wall is there to keep the plant strong when water is lost, it's only the inner cell membrane which detaches itself from the cell wall. However how does this explain the shrinking (plasmolysed) plant cell?
Many Thanks. :D

The cell wall stays the same shape, it is only the cell membrane that shrinks in a hypertonic solution (:

The answer is osmosis. Osmosis is defined as the diffusion of water across a cells semi-permeable membrane, and only refers to water.
The rule of diffusion is that a substance will move from an area of high concentration to an area of low concentration until equal.
If the cell is in an area with a higher water concentration of the outside of the cell than the inside, the water will diffuse from the area of high concentration to the area of low concentration.
This will leave the leave looking wilted and dehydrated.