Guttation
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Guttation is the appearance of drops of xylem sap on the tips or edges of leaves of some vascular plants, such as grasses.
At night, transpiration usually does not occur because most plants have their stomata closed at night. When there is a high soil moisture level, water will enter plant roots at night 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, forming drops. Root pressure provides the impetus for this flow, rather than transpirational pull.
Guttation fluid may contain a variety of organic compounds, mainly sugars, and mineral nutrients, mainly potassium.[1] On drying, a white crust remains on the leaf surface.
Guttation is not to be confused with dew, which condenses from the atmosphere onto the plant surface.
[edit] See also
[edit] References
- ^ Goatley, James L., Lewis, Ralph W. (March 1966). "Composition of Guttation Fluid from Rye, Wheat, and Barley Seedlings". Plant Physiology 41 (3): 373-375. Retrieved on 2006-10-31.
