from The American Heritage® Dictionary of the English Language, 5th Edition.
- noun A water-excreting microscopic epidermal structure in many plants.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun biology A
tissue, in the leavesof many plants, that contains microscopic poresthrough which wateris excreted.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- noun a pore that exudes water on the surface or margin of a leaf of higher plants
from The American Heritage® Dictionary of the English Language, 4th Edition
Even if the hydathode is treated with sublimate solution, all the conditions for mechanical filtration still remain: the earth has moisture which can be taken up by the roots so that root-pressure still exists.
The water which is forced upward by the root-pressure of the plant is naturally conveyed through the vascular fibres into the leaves and at every hydathode the superfluous water oozes out in drops, a phenomenon which one can also very nicely observe e.g. on the "Lady's cloak" (Alchemilla vulgaris) of the German flora.
In the first case the action of the hydathode should continue even after the treatment with the sublimate solution, while in the latter case it should not.