Question

List the criteria of essentiality of mineral element?

Answer 1

Essential Elements: An essential element is the one which has a specific structural or physiological role and without which plants cannot complete their life cycle.
Amon and Stout proposed criteria for knowing the essentiality of an element. They are :
(a) It is indispensable for the growth of plant.
(b) The element is directly involved in the nutrition
of plants. It becomes a component of either a structural or functional molecule. The element may additionally have a corrective effect of mineral balance and other soil conditions.
© A plant is unable to complete its vegetative or reproductive phase in the absence of the element, (d) The element cannot be replaced by any other element.
(e) The absence or deficiency of the element produces
disorders that are a direct result of the lack or deficiency of the element.
(f) The element alone can correct the disorders produced by its absence or deficiency.
16 elements have been found to be essential. They are C, H, O, N, P, K, S, Mg, Ca, Fe, B, Mn, Cu, Zn, Mo, Cl. Nickel has been made the seventeenth essential element

Answer 2

Answer:

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List the criteria of essentiality of mineral element_??

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Criteria for Essentiality

The criteria to determine the essentiality of an element include the following aspects.

1. The element must be absolutely necessary for supporting normal growth and reproduction of plants. In the absence of the element, the plants do not complete their life cycle or set the seeds.

2. The element must be directly involved in the metabolism of the plant. It should form a component of either a structural or functional molecule.

3. The requirement of the element must be specific and not replaceable by another element.

4. Absence or reduced availability of the element causes disorders.

5. The disorders caused by absence or deficiency of an element can be corrected only by the availability of that element.

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Based upon the above criteria, 17 elements have been found to be essential for plant growth and metabolism. They are C, H, O, N, P, K, Ca, Mg, S, Fe, B, Mn, Cu, Zn, Mo, Cl and Ni. Others are called non-essential elements.