Manganese competes with _________ and _________ for uptake, but...

Manganese toxicity is characterised by 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 to the shoot apex.

Therefore, excess of manganese may induce deficiencies of iron, magnesium, and calcium.

Answer: Iron and Magnesium