HORTICULTURE

Detailed explanation-1: -The cohesion – tension theory of sap ascent explains how how water is pulled up from the roots to the top of the plant. Evaporation from mesophyll cells in the leaves produces a negative water potential gradient that causes water and minerals to move upwards from the roots through the xylem.

Detailed explanation-2: -The upward movement of sap containing water and dissolved minerals from the root cells to xylem is called the ascent of sap.

Detailed explanation-3: -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. Cohesion (water sticking to each other) causes more water molecules to fill the gap in the xylem as the top-most water is pulled toward the stomata.