What is cohesion tension theory?

Cohesion Tension theory was proposed by botanist Henry Dixon in 1939. It states that water in xylem is pulled upward by air's drying power, which creates a continuous negative pressure called tension. The tension extends all the way from leaves to the roots that may be 100 feets below. read more

The cohesion-tension theory is a theory of intermolecular attraction that explains the process of water flow upwards (against the force of gravity) through the xylem of plants. It was proposed in 1894 by John Joly and Henry Horatio Dixon. read more

The cohesion-tension theory describes how water moves from the roots to the leaf. Osmosis causes water to enter the xylem of roots from the soil. Due to the hydrogen bonding between the water molecules, water forms a string of molecules as it moves to the xylem. read more

The cohesion-tension theory suggests that water is obtained in plants from soil due to the fact that water is cohesive and so is able to be drawn up from soil particles into the root hairs via osmosis. Water is then able to move through to neighbouring cortex cells by osmosis until it reaches the xylem. read more