image credit: Hanson59 ccGuttation is the exudation of drops of sap on the tips or edges of leaves of some vascular plants, such as grasses. Guttation is not to be confused with dew, which condenses from the atmosphere onto the plant surface. When there is a high soil moisture level, water will enter plant roots, because the water potential of the roots is lower than in the soil solution.
The water will accumulate in the plant, creating a slight root pressure. The root pressure forces some water to exude through special leaf tip or edge structures, hydathodes or water glands, forming drops. Here is a beautiful gallery that shows examples of guttation.
