Question

How does ascent of sap occur in tall plants?

Answer 1

The ascent of sap is the transport of the water and the inorganic minerals in the plant in the upward direction from the roots to the leaves. The root pressure theory does not explain the pressure which is involved in the process of transport. Root pressure is not enough to transport water in tall trees. The transpiration pull theory is based on the pressure which is created due to transpiration, adhesion and cohesion forces. There is cohesive force between the water molecules. There is adhesion force between water and xylem elements. The force is created due to loss of water due to transpiration which helps in the conduction of water in tall trees.