Question

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

Answer 1

Toxicity:

Micronutrients if present in large amounts (above their critical concentration) leads to toxicity. The main effect of this toxicity is that the uptake of other elements are affected.

Manganese toxicity leading to deficiency of Ca, Mg and Fe:

Manganese toxicity has the following effects:-

● It competes with iron and magnesium for uptake which results in reduction in their uptake.

● It competes with Mg for binding to the enzymes, thus affecting enzyme interaction.

● It inhibits the translocation of calcium in the shoot apex. As a result, the plant shows deficiency symptoms of Ca, Mg, Fe.

Manganese toxicity symptoms:

Manganese toxicity is characterised by the appearance of brown spots surrounded by chlorotic veins.