You observe that a plant's younger leaves, not the older ones, are yellowing. You recall that the cause of plant sickness can be diagnosed by which leaves are yellowing. What is the most likely cause of your plant's blight?

Options

A. Too much shade
B. Lack of nitrogen-fixing Rhizobium bacteria
C. A deficiency in a mobile mineral nutrient
D. A deficiency in a non-mobile mineral nutrient

Answer

D

Explanation

Deficiency symptoms of immobile elements tend to appear first in the young tissues because the elements are relatively immobile and are not transported out of mature organs, e.g., elements lik,e sulphur and calcium are a part of the structural component of the cell and hence are not easily released.