Describe briefly

The three physical properties of water which helps in ascent of water in xylem are:

i) Adhesion: It is the attraction between water molecules and other molecules other than water molecules (here surface of the xylem vessel).

ii) Cohesion: Cohesion is the force due to which molecules of water stay linked together due to hydrogen bonding in between them. It provides strength against the pressure by the transpiration pull.

iii) Surface tension: It is the property of the surface of a liquid to resist an external force applied owing to the cohesive nature of the molecules of the liquid.

Capillary action is a result of adhesion and cohesion.

(Hydrogen bonding and dipolarity explain adhesion and cohesion)