Question

The principle driving force behind movement of water in plants is known as

• A. Ionic potential
• B. Membrane potential
• C. Soil temperature
• D. Water potential

Hint:

Water moves from high to low water potential—this concept is key to understanding root absorption, xylem transport, and transpiration in plants.

Answer 1

The Correct Option is D

Step 1: Understand water movement in plants. 
Water moves in plants primarily through processes like osmosis, transpiration pull, and root pressure. The direction of water movement depends on the water potential gradient. 
Step 2: What is water potential? 
Water potential (\( \Psi_w \)) is a measure of the potential energy of water in a system compared to pure water, and it determines the direction of water movement. Water always moves from a region of higher (less negative) water potential to a region of lower (more negative) water potential.
Step 3: Eliminate incorrect options.
Ionic potential refers to charge-based ion properties.
Membrane potential relates to charge difference across membranes, not water movement.
Soil temperature affects water absorption rate but is not the driving force.
Therefore, Water potential is the correct answer.