Water goes up through xylem vessels in tall trees. The process in plan

Water goes up through xylem vessels in tall trees. The process in plants and properties of water that help in upward movement are :

[amp_mcq option1=”Respiration and cohesion” option2=”Transpiration pull, cohesion and adhesion” option3=”Root pressure, cohesion and adhesion” option4=”Transpiration and adhesion” correct=”option2″]

This question was previously asked in

UPSC CDS-2 – 2023

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Water movement upwards through xylem vessels in tall trees is primarily explained by the cohesion-tension theory, which relies on transpiration pull, cohesion, and adhesion.

Transpiration pull is the force generated by the evaporation of water from the leaves (transpiration). This pull creates tension in the water column within the xylem. Cohesion is the property of water molecules to stick together due to hydrogen bonding, maintaining an unbroken water column. Adhesion is the property of water molecules to stick to the hydrophilic walls of the xylem vessels, preventing the water column from breaking and helping it climb upwards against gravity.

Root pressure is another mechanism that can push water upwards, but its effect is generally limited and insufficient to raise water to the tops of tall trees, especially during the day when transpiration rates are high. Respiration is a metabolic process for energy release and is not directly involved in the upward movement of water.

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