Question

Why is that in plant cretain deficiency symptoms appear first in younger parts of the plants while in other they do so in mature organs

Answer 1

Deficiency symptoms are morphological changes in plants, indicating nutrient deficiency. Deficiency symptoms vary from one element to another. The plant part in which a deficiency symptom occurs depends on the mobility of the deficient element in the plant. Elements such as nitrogen, potassium, and magnesium are highly mobile. These elements move from the mature organs to the younger parts of a plant. Therefore, the symptoms for the deficiencies of these elements first appear in the older parts of the plant. Elements such as calcium and sulphur are relatively immobile. These elements are not transported out of the older parts of a plant. Therefore, the symptoms for the deficiencies of these elements first appear in the younger parts of the plant.

Answer 2

Answer:

Mobility of a deficient element decides the appearance of symptoms. If the element is relatively immobile then symptoms appear in young parts and if the deficient element is mobile, then symptoms appear in older parts of the plant.