Question

Funtional element was introduced by _______

• A. Nicholas
• B. Priestly
• C. Warrington
• D. Arnon

Hint:

Arnon and Stout (1939) proposed the "Criteria of Essentiality" for plant nutrients.
D. J. D. Nicholas (1961) introduced the term "Functional Element" to include both essential and beneficial elements (such as Co, Si, Na, V) involved in plant metabolism.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
In plant nutrition, mineral elements are categorized based on their physiological roles.
Arnon and Stout (1939) established the "Criteria of Essentiality," which defined 16 (now 17) elements as essential for plant growth and reproduction.
Later, other beneficial elements were identified that improve plant performance under specific conditions but do not meet all criteria of essentiality.

Step 2: Detailed Explanation:
The concept of a functional nutrient or functional element was proposed by D. J. D. Nicholas in 1961.
Nicholas defined a functional element as any mineral element that plays a role in plant metabolism, whether or not its role is specific or meets the strict criteria of essentiality.
This broader definition includes both the essential elements and beneficial elements like cobalt ($\text{Co}$), sodium ($\text{Na}$), silicon ($\text{Si}$), and vanadium ($\text{V}$).
These beneficial elements are not essential for all plant species but are functional because they support metabolic processes or enhance growth and stress tolerance in specific groups (such as silicon in rice or cobalt in nitrogen-fixing legumes).
Let us review the other options listed:
1. Joseph Priestley: Discovered oxygen in 1774 and demonstrated its production by plants during photosynthesis.
2. Katherin Warrington: Demonstrated the essentiality of boron for plants in 19
3. Daniel Arnon: Formulated the criteria of plant nutrient essentiality along with Perry Stout.

Step 3: Final Answer:
The concept of functional elements was introduced by Nicholas, which corresponds to Option (A).