Mechanism of Absorption of Water

Estimated time: 2 minutes

Maharashtra State Board: Class 12

Key Points: Mechanism of Absorption of Water

Modes of Absorption: Water is absorbed by plants through two methods: passive absorption and active absorption.
Passive Absorption: It is the main method (about 98%) where water is absorbed due to transpiration pull without using energy (ATP), mainly during daytime.
Driving Force in Passive Absorption: Transpiration creates negative pressure (tension) in xylem, which pulls water upward along the DPD gradient.
Active Absorption: Water is absorbed by root cells using energy (ATP) against the gradient, mainly during the night when transpiration is low.
Types of Active Absorption: Active absorption is of two types: osmotic (based on osmotic gradient and root pressure) and non-osmotic (requires direct energy and occurs against a concentration gradient).