Question

It is observed that deficiency of a particular element showed its symptoms initially in older leaves and then in younger leaves.

a. Does it indicate the element is actively mobilized or relatively immobile?

b. Name two elements which are highly mobile and two which are relatively immobile. c. How is the aspect of mobility of elements important to horticulture and agriculture?

Answer 1

The elements which cannot actively move within the plant are termed as immobile elements. If these elements are deficient or unavailable, the fraction available within the older parts of the plant will not get mobilised to the younger parts. Hence, deficiency symptoms will appear first in younger plant parts.


Case-specific conclusion:

In this case, since the deficiency of a particular element showed its symptoms initially in older leaves and then in younger leaves, hence, it must be the deficiency of a mobile element. This implies that the element is actively mobilised and not immobile.

b. Examples of mobile elements:

The elements which can actively move within the plant are termed as mobile elements. Examples: Nitrogen, potassium

Examples of immobile elements:

The elements which cannot actively move within the plant are termed as immobile elements. Examples: Calcium and sulphur

c. Significance:

Finding the cause of the deficiency diseases is particularly difficult. Therefore, by understanding the aspect of mobility of elements, the nature and the cause of the disease can be found easily by the agriculturalists and horticulturalists.