Question

For qualifying as an essential nutrient, element must satisfy the essentiality criteria propounded by D.I. Arnon and P.R. Stout in the year -

• A. 1937
• B. 1938
• C. 1939
• D. 1940

Hint:

Remember: Arnon & Stout (1939) proposed the criteria of essentiality using tomato plants. These rules help differentiate "essential" nutrients from "beneficial" elements (like Na, Si, Co, Se).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The criteria of essentiality establish whether an inorganic element is required for plant growth and development. This concept was formulated by D.I. Arnon and P.R. Stout.

Step 2: Detailed Explanation:
1. In 1939, Arnon and Stout proposed three conditions for an element to be considered essential:
- The plant cannot complete its life cycle (vegetative or reproductive phases) in the absence of the element.
- The deficiency of the element is specific to that element and cannot be replaced by any other element.
- The element must be directly involved in the nutrition and metabolism of the plant.
2. These criteria were later refined by Arnon in 1954.

Step 3: Final Answer:
The criteria of essentiality were propounded in the year 1939.