Question

When a stem of a plant is cut a few inches above the soil and xylem sap is seen flowing out through the cut end, this exudation is considered evidence for the existence of root pressure. Who proposed the theory of root pressure?

• A. Robert Hooke.
• B. Stephen Hales.
• C. Joseph Priestley.
• D. Gregor Mendel.

Hint:

Root pressure is a key concept in plant physiology and helps explain how water and nutrients move from roots to shoots in the absence of transpiration.

Answer 1

The Correct Option is C

Step 1: Root Pressure Explained.
Root pressure arises from the active uptake of water and minerals by roots, creating hydrostatic pressure that drives xylem sap upwards. 
Step 2: Historical Context. 
Joseph Priestley investigated root pressure and sap exudation, underscoring the significance of osmotic gradients in plant water transport. 
Step 3: Contrasting Contributions. 
Robert Hooke: Contributed to cell theory, not root pressure. 
Stephen Hales: Researched plant physiology but did not theorize root pressure. 
Gregor Mendel: Pioneer of genetics, unrelated to root pressure.