Hydathodes


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Hydathodes

 

adaptations in plants for the excretion of tiny droplets of moisture (guttation).

Hydathodes serve for the passive exudation of surplus water through the epidermal pores under the effect of root pressure. They are found primarily in plants with weak transpiration that live in conditions of excessive soil moisture. The hydathodes are located on the apexes of the leaves or on the tips of the laminar denticles. In the majority of plants they are modified stomata whose guard cells never close. The pore is sometimes surrounded by ordinary epidermal cells. Some hydathodes are actively moisture-excreting glandulae.

O. N. CHISTIAKOVA

References in periodicals archive ?
cells of hydathodes following transpiration and guttation one after
guttation water out of hydathodes (Kim & Steudle, 2009).
physiological functions of hydathodes lies in the retrieval of
Keywords: macrophytes, Fabaceae, hydathode trichome.
Multicellular trichomes are present on the petiole of all evaluated species, classified in four types according to their shape and structure: hydathode trichome (Figure 2A), long cone-shaped trichome (Figure 2B), bulb-like base trichome (Figure 2C), and short cone-shaped trichome (Figure 2D), with distinct distribution among the species, and easily differentiated under SEM (Figure 2E-G).
Hydathode trichome, present on the petiole and on the margin of the leaflets of A.
5 mm apart, diverging at 75-85[grados] from costa; hydathodes absent; fertile fronds not seen.
1 mm apart, diverging at 75-85[grados] from costa; hydathodes absent; fertile fronds 22-33 cm long; stipes 1/5-2/5 of frond length; fertile blades 15-27 x 1.
5 mm apart, diverging at 65-80[grados] from costa; hydathodes absent; fertile fronds 42-57 cm long; stipes 1/2-3/4 the frond length; fertile blades 12-22 x 2.
3 mm, linear to subulate, dark brown to atropurpureous, marginally entire, only on blade margin and rarely on base of costa, dispersed of absent; few evident veins, simple or 1-forked, 1-2 mm apart, diverging at 60-75[grados] from costa; hydathodes absent; fertile fronds 30-45 cm long; stipes 3/5-4/5 the frond length; fertile blades 10.
2-3 mm apart, diverging at 70-80[degrees] angle from costa; hydathodes evident, dark brown to blackish; fertile fronds 37-55 cm long; stipes 3/4-4/5 of the frond length; stipe scales 1-3 x 0.
6 mm, lanceolate, dark brown, rolled, dense; veins simple to 1-forked, 1-2 mm apart; hydathodes absent; fertile fronds 25-37 cm long; stipes 2/5-2/3 the frond length; fertile blades 8-16 x 1.