Question

Correct sequence in water absorption by root hairs.

• A. Imbibition, diffusion, osmosis.
• B. Osmosis, imbibition, diffusion.
• C. Diffusion, imbibition, osmosis.
• D. Osmosis, diffusion, imbibition.

Hint:

Water absorption in plants begins with imbibition, followed by diffusion into root hair cells, and ends with osmosis into the root cortex.

Answer 1

The Correct Option is A

Phase 1: Comprehending water uptake mechanics.
Root hairs absorb water through three sequential phases:

 Imbibition: Initial water uptake by hydrophilic materials (e.g., cellulose in cell walls) via capillary action. 

Diffusion: Following imbibition, water moves from areas of high concentration (soil solution) to lower concentration (root hair cells). 

Osmosis: Ultimately, water translocates across the semipermeable membranes of root hair cells into the root cortex, driven by osmotic gradients. 

Phase 2: Elucidation of the proper order. 
The correct progression of water absorption is: \[ \text{Imbibition} \rightarrow \text{Diffusion} \rightarrow \text{Osmosis}. \] Imbibition initiates the process as cell walls absorb water. Diffusion then facilitates water transport to the root hair cytoplasm. Osmosis enables water movement across membranes into interior root cells. 

Phase 3: Analysis of alternative sequences. 
Option (B): Incorrect. Osmosis is not the initial step; imbibition occurs prior to it. 

Option (C): Incorrect. Diffusion does not precede imbibition. 

Option (D): Incorrect. Osmosis follows diffusion, not the reverse. \[ \therefore \text{The correct sequence is: Imbibition, diffusion, osmosis.} \]