HORTICULTURE

Detailed explanation-1: -Capillary action helps bring water up into the roots. But capillary action can only “pull” water up a small distance, after which it cannot overcome gravity. To get water up to all the branches and leaves, the forces of adhesion and cohesion go to work in the plant’s xylem to move water to the furthest leaf.

Detailed explanation-2: -The direction of xylem transport is upwards and unidirectional i.e. from roots to other plant parts. The water column moves only upwards because of the two forces, transpirational pull, and positive root pressure.

Detailed explanation-3: -As transpiration occurs, it deepens the meniscus of water in the leaf, creating negative pressure (also called tension or suction). The tension created by transpiration “pulls” water in the plant xylem, drawing the water upward in much the same way that you draw water upward when you suck on a straw.

Detailed explanation-4: -The xylem wall is also polar and hence can form intermolecular associations with water molecules. As water molecules move up the xylem via capillary action, they pull inward on the xylem walls to generate further tension.