Tuesday, April 17, 2018

Guttation: April Word of the Month

Photo courtesy Noahelhardt/wikimedia commons
Have you ever noticed tiny water droplets uniformly spaced around the margins of a leaf on a dewy morning? If so, you might have wondered what would cause dewdrops to form in such a regular pattern. In fact, you have observed a phenomenon called “guttation.”

Photo courtesy University of Missouri IPM
Guttation is a process by which plants exude water from structures called hydathodes on margins or tips of leaf blades. In a sense, guttation is Mother Nature’s way of allowing plants to relieve water pressure that can build up in their tissues under certain conditions.

The water is from xylem — the main water transport tissue in a plant. Usually, extra water escapes through tiny holes in the plant’s leaves and stem called stomata. But sometimes, those stomata are closed. When that happens, the pressure from water entering the roots continues to force water up through the plant. The water — and nutrients it picks up on the way — forces its way out as droplets at the tips and edges of leaves.

Regardless if its effects on plants, guttation provides entertainment to plant lovers. Check it out on your next dewy garden walk!

For more information:
Science News for Students: Scientists Say “Guttation”