Component 3.2 - Movement Of Water From Roots To Leaves

Question 1

Describe the cohesion tension theory

Answer 1

Water has hydrogen bonding and a dipole structure, therefore water molecules are attracted towards each other which is cohesion.

As water is drawn up in the root, it evaporated from the leaf pulling up the other water molecules behind it which is called tension.

Adhesion is when water molecules are attracted to the hydrophilic lining of the xylem

These all help water move up the xylem

Question 2

What is root pressure?

Answer 2

A consequence of osmotic movement of water going down a concentration gradient at the base of the xylem due to uptake of ions pushing water already there further up.

Question 3

What other mechanisms move water up plant?

Answer 3

Capillarity