Question

What is Guttation?

Answer 1

Hint: This process along with transpiration gives a cooling effect to the plant.

Complete answer:
The secretion of drops of xylem sap from hydathodes on the tips or edges of leaves of some vascular plants, such as grasses, and several fungi is called guttation. It generally happens at night and early morning.
 During the day time transpiration decreases the rate of guttation, guttation slows also because of quick evaporation due to excessive sunlight. Water can rise to 2 feet on its own through the xylem of the plant.
 It is an important process of removal of extra water from plants, in this way plants balance the amount of water they absorb. Guttation is caused because of root pressure and also it causes permanent loss of water. It is not dew. From the atmosphere, dew condenses onto the plant surface. By guttation and transpiration, plants release the excess absorbed water, this cools the plant and the surrounding atmosphere as well. This cooling takes place when the surrounding atmosphere becomes hot.
The process of guttation cannot be mixed with the process of bleeding in plants.

Note:
1. Hydathodes are a type of pore which secrete water and are present on leaf margins. They are commonly found in angiosperms.
2. In rare cases, guttation bacteria can grow on droplets and can be pulled back into the leaf when the sun comes up, leading to disease infection.
3. Bleeding is the excessive loss of water from the cut or injured part of the plant.