guttation


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Related to guttation: Hydathodes
Guttationclick for a larger image
Fig. 184 Guttation . Transverse section of a saxifrage leaf.

guttation

the emergence of water from the endings of leaf veins, usually occurring at night when TRANSPIRATION is low or absent. Guttation is thus a method of exuding excess water and involves special water pores called HYDATHODES at leaf tips which, unlike normal STOMATA, are not able to control their aperture size. The process is common in low-growing plants such as grasses.