Select the correct statement regarding manganese toxicity.
- Appearance of brown spots surrounded by chlorotic veins
- inhibition of Ca translocation in shoot apex
- induction deficiencies of Mg and Fe
- all of these
Solution: Answer: DSolution: Manganese toxicity (brown spots surrounded by chlorotic veins) is due to:
(i). Reduction in uptake of iron and magnesium.
(ii). Inhibition of binding of magnesium to specific enzymes.
(iii). Inhibition of calcium translocation into shoot apex. Therefore, excess of manganese causes deficiency of iron magnesium and calcium.