Water me!

Water makes up about 95% of the fresh weight of a plant. Water is essential for plants to take up nutrients from the soil and deliver them through the plant body. Water is also essential for maintaining the turgor of a plant. By filling the cells with enough water to exert pressure against the cell walls, the cells provide the strength necessary to support the plant. When water becomes limiting, plants are said to "wilt". WIlting occurs when water availability is seriously limiting and can lead to damage or death if wilting goes on too long. Fortunately, if additional water is provided before serious damage occurs, a plant will quickly rehydrate and resume normal growth and metabolism. The time-lapse movie here shows a coleus plant wilting as the soil in the pot become progressively drier. Upon watering, the turgor rapidly returns and the plant recovers from the wilting period.

The wilting portion of the movie was filmed over three days. As the turgor pressure in leaf cells decrease, the cells signal the guard cells to close the stomata, thus slowing the loss of water. Once water becomes availlable again, recovery is rapid. The last segment showing recovery after water only took about three hours compared to the three days it took to wilt.