Explain how plants without a heart can pump water up sometim

Explain how plants without a heart, can pump water up sometimes hundreds of feet above ground. Base you explanation in the characteristics of water molecules and water potentials.

Solution

Plants have no pumping organ like \'heart\' to drive water or sap(water with dissolved solutes) upwards.Yet, transport of sap occurs which is critical for its survival. This process of upward transport of sap, from roots to the plant tip, via xylem vessels, is known as \'Ascent of sap\' or \'Xylem conduction\'.

The process can be explained by \'Cohesion-Adhesion-Tension\' theory proposed by H.H.Dixon and J.Jolley. The theory is based on following assumptions:

1)Properties of water: Cohesion (intermolecular forces) and Adhesion (intramolecular forces).

2)Existence of continuous, unbroken, column of water in xylem vessels due to cohesion and adhesion.

3)Transpiration pull

The theory is summarized as follows: