1. Cohesion: Water molecules are highly attracted to each other due to hydrogen bonding. This strong attraction creates a cohesive force, allowing water molecules to form a continuous column within the xylem vessels.
2. Adhesion: Water molecules are also attracted to the walls of xylem vessels, which are made of lignin. This adhesion helps to counteract the force of gravity and keeps the water column from breaking.
These two properties work together in a process called transpiration pull. As water evaporates from the leaves, it creates a negative pressure within the xylem. This negative pressure pulls on the cohesive water column, drawing water up from the roots. The adhesion of water molecules to the xylem walls prevents the column from collapsing.
