Beautiful examples of guttation (12 pictures)
Guttation is the exudation of drops of sap (xylem) 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.
At night, transpiration usually does not occur because most plants have their stomata (pores found in the epidermis of leaves, stems and other organs that are used to control gas exchange) closed.
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. Root pressure (osmotic pressure within the cells of a root system that causes sap to rise through a plant stem to the leaves) provides the impetus for this flow, rather than transpirational pull. [Source: Wikipedia]
Photograph by URSULA ROSEEU
Photograph by JOHN PETRANKA on Flickr
Photograph by RUTH JENSEN
Photograph by Ies on Wikimedia Commons
Photograph by NOAH ELHARDT
Photograph by TANAKAWHO
Photograph by AlexRK on Flickr
Photograph by nz_willowherb on Flickr