Name the two theories which explain water movement in stems. Give the explanation of root pressure theory.
There tire two theories which explain water movement in stems are
(i) root pressure theory and (ii) adhesion-cohesion theory.
Root Pressure Theory
(i) Root pressure is a positive hydrostatic pressure developed in the root cortical cells, which pushes the water up to certain height in the xylem vessels.
(ii) The root cells actively absorb the mineral ions from the soil and accumulate them in the root.