Most accepted theory for ascent of sap is
capillary theory
root pressure theory
pulsation theory
transpiration pull
D.
transpiration pull
Transpiration pull or the suction force is the force which aids in drawing the water upward from roots to leaves. In leaves, some amount of water is used for photsynthesis and excess of water is released into atmosphere through openings called as stomata.
Root Pressure Theory is the transverse osmotic pressure within the cells of a root system that causes sap to rise through a plant stem to the leaves.
Pulsation theory or Vital force theory was not accepted because living cells are not involved in the ascent of sap as water continue to rise upwards in the plant.
Capillarity Theory is the capillarity movement of water due to adhesion and cohesion forces balanced by downward pull of gravity.
