Water moves up against gravity and even for a tree of 20m height, the tip receives water within two hours. The most important physiological phenomenon which is responsible for the upward movement of water is _______________________.

Question

Philoid · Accepted Answer

Transpiration pull

Transpiration pull is the process responsible for the upward movement of water against gravity even for a tree of height up to 20m.

As the plant performs transpiration via stomata, it pulls water molecules upward to the leaf via xylem (adhesion and cohesion of water molecules). This creates a pressure gradient between the atmosphere and sub-stomatal cavity. This is transferred to the intercellular spaces of leaf then to xylem of the leaf vein. This pull is called the transpiration pull.