A very thin long and
slender tube with a small internal diameter that holds liquid by
capillary action.
Capillary action
or Capillarity
[
Physics -
Botany ]
The natural
phenomenon by which
water is raised of from a wet
area and transported to a dry area
through pores,
fibres or very small opening
(capillary tubes), of a material
with or against the law of gravity.
Capillary action or
capillarity is the ability of a living
tissue,
material, or object containing
minute openings or passages, (as capillary tube,
fibres and
pores), to rise the surface
of water (or of other liquid)
upwards above the hydrostatic level against the force of gravity.
It occurs - despite the force of gravity - through the combined
effects of pressure, adhesion, cohesion, viscosity
and surface tension, when the adhesive intermolecular forces between
the liquid and a solid are stronger than the cohesive intermolecular
forces within the liquid. The effect causes the spontaneous movement
of liquid through the tiny spaces in material, such the upward
movement of water in the
soil. The same effect is what
causes porous materials to
soak up liquids
This is similar to how plants
seemingly defy gravity when they transport liquid from the
roots upward through the plant.
The capillarity is the process by which water travels or rises in the
interstices of a porous medium
(e.g. in tiny spaces between soil
particles, rocks, sediments and
potting mixes) caused by the cohesion between water molecules and an
adhesion between water and other materials that "pulls" the water
upward.
In popular home gardening are commonly used self-watering devices, which
employ capillary action to drawn up water form a reservoir into the soil
of a pot.
Some species of climbing
plants develop holdfast roots which help to support the vines on
trees, walls, and rocks. By forcing their way into minute pores and
crevices, they hold the plant firmly in place.
Climbing plants, like the poison ivy (Toxicodendron
radicans), Boston ivy (Parthenocissus
tricuspidata), and trumpet creeper (Campsis
radicans), develop holdfast roots which help to
support the vines on trees, walls, and rocks. By forcing their
way into minute pores and crevices, they hold the plant firmly
in place. Usually the Holdfast roots die at the end of the first
season, but in some species they are perennial. In the tropics
some of the large climbing plants have hold-fast roots by which
they attach themselves, and long, cord-like roots that extend
downward through the air and may lengthen and branch for several
years until they strike the soil and become absorbent roots.
Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House,
1994
