Ncert Exercises & Solutions

Excess of Mn in soil leads to deficiency of Ca, Mg and Fe. Justify

Manganese (Mn⁺²) becomes toxic when absorbed by plants in higher amounts. The toxicity expressed in form of brown spots surrounded by chlorotic vein.

It is due to the following reasons

(i) Reduction in uptake of Fe³⁺ and Mn⁺².

(ii) Inhibition of binding of Mn⁺² to specific enzymes.

(iii) Inhibition of Ca²⁺ translocation in shoot apex.

Thus, excess of Mn⁺² causes deficiency of iron, magnesium and calcium.