Question

-----------------established the essentiality of Vanadium in microorganisms.

• A. Broyer 1954
• B. McCargue 1954
• C. Nicholas 1961
• D. Thomas & Way 1907

Hint:

Associate "Nicholas (1961)" with "Vanadium essentiality in microorganisms" (alternative nitrogenase cofactor).
Associate "Broyer (1954)" with the discovery of "Chlorine (\(\text{Cl}\)) essentiality in plants."

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
While plants require 17 essential nutrient elements, certain microorganisms and lower plants require additional beneficial elements to activate specific metabolic enzymes or pathways.

Step 2: Detailed Explanation:
Vanadium (\(\text{V}\)) is a beneficial micro-element required by certain nitrogen-fixing bacteria, such as Azotobacter chroococcum.
In 1961, the renowned microbiologist and plant physiologist D. J. D. Nicholas established that vanadium is essential for these microorganisms.
He demonstrated that under molybdenum-deficient conditions, certain nitrogen-fixing bacteria can utilize a vanadium-containing nitrogenase enzyme (V-nitrogenase) to reduce atmospheric dinitrogen to ammonia, proving that vanadium can substitute for molybdenum in this pathway.
Analyzing other options:
- Broyer et al. (1954) established the essentiality of Chlorine (\(\text{Cl}\)) for higher plants.
- Thomas and Way (1907) are famous for their early research on soil cation exchange and clay properties, not micronutrient essentiality.
Therefore, Nicholas (1961) is the correct scientist.

Step 3: Final Answer:
Nicholas (1961) established the essentiality of Vanadium in microorganisms.