Question

Give reason: Some deficiency symptoms of mineral are visible in young leaves while some appear in older leaves.

Answer 1

1. A mineral element is said to be deficient when its concentration falls below a specific critical level.
2. Symptoms appear in the form of various morphological changes in element mobility.
3. These symptoms are caused by the movement of elements within the plant body.
4. When the element is relatively immobile like S and Ca, then the symptoms appear first in young leaves.
5. When elements, such as N, Mg, and K, are actively mobilised within the plant body, they are transferred to young tissues, and the symptoms appear in older, i.e. senescent leaves.