The Three Theories of Transport in the Xylem

Cohesion tension
The problem of how water moves upward in plants from roots to shoots is most extreme in the tallest trees, where distances to be traveled are the greatest. Some of the tallest trees are at least 120 metres tall. If a hypothesis or model can explain water movement in these tallest plants, then the model can also explain it in smaller examples. Much of the research on the mechanism of water transport has been performed on relatively tall trees.
Since around the 1960s one mechanism has been the most widely accepted explanation for how water moves in the xylem. …