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The discharge of water from a plant surface, especially from a hydathode.



the exudation of water droplets by plant leaves, occurring when more water is absorbed by the roots than is evaporated by the leaves. It is observed mainly at night, in the early morning, or when plants are placed in a humid atmosphere; it is often observed in young sprouts, such as those of grains, whose root-system development overtakes the development of the evaporative surfaces of their leaves. The drops of water are secreted through water stomata under the action of root pressure, by the force of water pressing into the stems and leaves. Guttation is a physiological process connected with the life processes of the plant; if wheat sprouts are placed under a cone inside of which there is chloroform vapor, guttation ceases. Secretions of guttation always contain a number of mineral substances. Evidently guttation rids the plant of excess salts, mainly calcium.

References in periodicals archive ?
known to guttate upto 100-250 mL of water per night (Flood, 1919; Dixon
A diagnosis of Guttate Psoriasis was given and CBC with diff, CCP and RPR were ordered along with a dermatology referral.
Unlike psoriasis, guttate psoriasis is a much lesser known entity.
The exact cause is unknown, although guttate psoriasis may be followed by streptococcal infection such as tonsillitis.
Phototherapy (UVB) is indicated for patients with generalized plaque, guttate psoriasis, or palmoplantar psoriasis who have not responded adequately to conventional topical therapies.
Guttate psoriasis is a more common presentation in childhood and teenage years and will often be the first indication of the disease.
Guttate psoriasis is usually a self limiting disease lasting from 12 to 16 weeks without treatment, often developing in later years to the chronic plaque type psoriasis.
Clinically, the patients with plaque psoriasis were defined as "stable" psoriasis, while those with guttate psoriasis or with flare-up of guttate psoriasis in case of plaque psoriasis were defined as "active" psoriasis.
Guttate psoriasis is often triggered by tonsillitis.
Disorder takes many clinical forms in the childhood group, with punctate, guttate, nummulare and plaque-type lesions, diaper distribution, facial involvement, triggered by emotional factors and skin injury.