Question

Manganese toxicity causes:

• A. Reduces uptake of magnesium and iron
• B. Inhibit translocation of $C{a}^{2+}$
• C. Yellow spots surrounding chlorotic veins
• D. Both (a) and (b)

Answer 1

Answer: (D)

The prominent symptom of manganese toxicity is the appearance of brown spots surrounded by chlorotic veins. Manganese competes with iron and magnesium for uptake and with magnesium for binding with enzymes. Manganese also inhibits calcium translocation in the shoot apex. Therefore, excess of manganese may, in fact, induce deficiencies of iron, magnesium and calcium.