Question

Electro-osmotic theory for translocation of organic solutes was given by

• A. Mason & Phillis
• B. Fenson & Spanner
• C. Van den Honert
• D. De Varies & Curtis

Hint:

Associate "Electro-osmotic theory" directly with Spanner and Fenson.
The core concept is that potassium (\(K^+\)) ions cycle across the sieve plate to generate an electric potential difference that pulls hydrated solutes through sieve pores.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Long-distance translocation of organic solutes (primarily sucrose) takes place through sieve elements in the phloem.
Several theories have been proposed to explain the mechanism driving this solute movement.

Step 3: Detailed Explanation:
- Fenson & Spanner (B): Proposed the Electro-osmotic theory (Fenson in 1957, Spanner in 1958). They suggested that an electric potential gradient across the sieve plates drives the electro-osmotic flow of water and dissolved solutes through the pores of sieve plates.
- Mason & Phillis (A): Contributed to theories on activated diffusion and pressure flow.
- Van den Honert (C): Associated with the interfacial thermodynamic flow model.
- De Vries & Curtis (D): Focused on cytoplastic streaming and diffusion theories.

Step 4: Final Answer:
The electro-osmotic theory was proposed by Fenson & Spanner, matching option (B).