Choose the correct essentiality criteria for mineral element A) Deficiency of any element can be met by supplying some other element B) Element must be involved in the metabolism of the plant C) Plant do not complete their life cycle without the element D) Few elements have been found to be absolutely essential for growth of the plant
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Remember that "specificity of requirement" is a core tenet of mineral essentiality.
If element X is deficient, only element X can correct that deficiency. No other element can substitute.
Step 1: Understanding the Question:
The question asks to identify the correct criteria for the essentiality of a mineral element in plants from the given statements.
The criteria for essentiality were established by Arnon and Stout to determine whether a mineral is indispensable for plant growth and reproduction.
Step 2: Key Concepts and Approach:
According to the established criteria of plant mineral nutrition:
1. The element must be absolutely necessary for supporting normal growth and reproduction. In its absence, the plant cannot complete its life cycle or set seeds.
2. The requirement of the element must be specific and cannot be replaced by supplying any other element.
3. The element must be directly involved in the metabolic processes of the plant.
Step 3: Detailed Explanation:
• Statement A: This statement is incorrect because the requirement of an essential element is highly specific.
Its deficiency cannot be resolved by substituting it with any other structurally or chemically similar element.
• Statement B: This statement is correct. The element must play a direct role in the plant's physiological and biochemical metabolism (e.g., as a cofactor for enzymes).
• Statement C: This statement is correct. Without the essential element, plants exhibit severe deficiency symptoms and are unable to complete vegetative or reproductive phases of their life cycle.
• Statement D: This statement is correct. Out of more than 105 minerals found in various plants, only a select group of 17 elements are identified as absolutely essential for growth.
Step 4: Final Answer:
Therefore, statements B, C, and D are correct criteria, making option (D) the correct choice.
