Question

Deficiency symptoms of nitrogen, magnesium, and potassium are visible first in:

• A. Senescent leaves
• B. Young leaves
• C. Roots
• D. Buds

Answer 1

The correct option is A Senescent leaves

The deficiency of potassium in plants is first visible in the older leaves. They start turning yellow and brown scorches are also seen. Similarly, the first symptoms of nitrogen and magnesium deficiency in plants are also observed in the yellowing of older leaves. This is because plants are unable to make enough chlorophyll and hence start appearing pale green or yellow. Whatever nitrogen, magnesium, or potassium was there in the older leaves are now mobilized to younger leaves.

Yellowing of leaves occurs first in younger leaves in the deficiency of some other nutrients, like sulphur and iron.