NEET BIOLOGY

Detailed explanation-1: -The cohesion-tension hypothesis states that transpiration drives xylem water flow. It causes –2 MPa negative pressure (tension) at the leaf surface. This strain draws up water from the roots. Negative water potential attracts soil water into root hairs and xylem.

Detailed explanation-2: -According to the cohesion-tension theory, transpiration is the main driver of water movement in the xylem. It creates negative pressure (tension) equivalent to –2 MPa at the leaf surface. Water from the roots is ultimately pulled up by this tension.

Detailed explanation-3: -Cohesion-tension-transpiration pull model was originally proposed by Dixon and Jolly in 1894 and further improved by Dixon in 1914. According to this theory, due to transpiration, the water column inside the plant is pulled up and that leads to ascent of sap.

Detailed explanation-4: -Transpiration pull is also referred as suction force and this force is used to draw the water in an upward direction from the roots to the leaves.

Detailed explanation-5: -This theory however describes the movement of water from roots to the leaves of a plant. Because of osmosis water from soil reach the xylem of roots of a plant. Water molecules are bonded to each other by hydrogen bonding, hence water form a string of molecules during its movement toward xylem.