Question

Which one of the following symptoms is not due to manganese toxicity in plants?

• A. None of the above
• B. Deficiency in both Iron and Nitrogen is induced
• C. Calcium translocation in shoot apex is inhibited
• D. Appearance of brown spot surrounded by chlorotic veins

Answer 1

The correct option is B Deficiency in both Iron and Nitrogen is induced

Toxicity

Micronutrients if present in large amounts leads to toxicity. One of the prominent effects of toxicity is that the uptake of other elements are affected due to interference.

Manganese toxicity

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


Effect on Iron uptake

Manganese toxicity has no effect on the uptake of nitrogen.

Final answer

b. Deficiency in both Iron and Nitrogen is induced