Biology:How is the Xylem able to transport water..?

Water goes up through the xylem of the plant by the transpiration pull. three different forces causes this 1. cohesion 2. adhesion and 3, tension. when water evaporates from the surface of a leaf cohesion causes other water molecules to bind to each other and pull up as transpiration occurs. adhesion causes these water molecules to attach to the walls of the xylem vessel and tension causes the vessel to narrow and this sends the water up at a powerful speed. this causes it to reach the top.

1) Root pressure
minerals and water from soil are sucked up by the root by active transport
minerals transported from epidermis to the centre of the root (where the endodermis prevents it from diffusing back into soil)
water enters through osmosis (the root is hypertonic to the soil)
creates pressure
pushes xylem water/sap up - root pressure

2) In the stem
the properties of water are strong to pull up water from xylem
adhesion: water clings to non-oily surface
therefore, water flows into the xylem walls
cohesion: water sticks to itself
the hydrogen bonding between the water is strong, so it makes a long chain of water molecules, that are as strong as steel of the same diameter!!

3) In the leaves
Transpiration Pull
transpiration is the loss of water in a leaf
as more water is evaporated from the leaves, the leaves lose more and more pressure
this causes the string of water molecules stuck together by cohesion to pull up - this is the leaf pull, or transpiration pull
(kind of like a sucking straw)

tension on the water column call go through a xylem in any tree in the world, and scientists even estimate that it is possible that xylem can travel up three times taller than the tallest tree in the world!!!