Drinking at the hydathone
What is the origin of the guttation-water? You have three choices. Choice one is from the soil. Choice two is the plant cover. Choice three is the atmosphere. Choice number one, not so much. The second choice is called guttation. Here liquid water “weeps” from the veins on the leaf’s margin and vascular system in general. Not dew. The correct choice is from the xylem water and is not water condensation of atmosphere onto the plant surface. The motive force to get the xylem water is the free energy gradient from soil to leaf. Veins.
Guttation is the loss of plant-water at the termination of a vein at a leaf Sometimes the guttation extends along the length veins of the vascular system. Most commonly guttation is on the morning following a good summer rain. On such days there is likely to be a high turgor pressure in the plant tissues.
Like stomates on leaves, lenticels on stems, guttation may be assisted by the presence of special cells called hydathodes. Hydathodes: who needs them? My first thought, as a one-time entomologist, was insect drinking fountains. The literature did not disappoint me. Girolami, V. (2009) and others, Translocation of neonicotinoid insecticides from coated seeds to seedling Guttation Drops. A NOVEL WAY OF INTOXICATION FOR BEES. In Ecotoxication 102(5):1808-1815. Using cornfields guttation, they found that bees at the pesticide hydathodes drinking foundation, bee death was “within minutes.” Implication: Colony Collapse Disorder (CCD)
Photo taken by: Noah Elhardt