Question

What is an evident symptom of manganese toxicity in plants?

Answer 1

Manganese:

1. Manganese is the micronutrient that plants obtain from the soil in very less amounts.
2. It is found in the soil as trivalent and tetravalent oxides.
3. It functions as an activator of certain enzymes such as malic dehydrogenase and oxalosuccinate (enzymes of the Krebs cycle).
4. Manganese is also involved in the synthesis of chlorophyll and oxidation of auxin.

Manganese toxicity in plants:

1. Toxicity is an increased concentration of an element in the plant.
2. Manganese toxicity occurs when the concentration of manganese increases in a plant.
3. This leads to the appearance of various symptoms such as yellowing of leaves, and the appearance of brown spots on leaves.
4. The appearance of yellowish-brown spots on the veins of the leaf is caused by manganese toxicity.
5. Manganese (Mn) is abundantly found in the soils, but its lower solubility at an alkaline pH or neutral pH prevents its uptake by the plants.
6. Sometimes waterlogging also causes manganese toxicity in plants.

Symptoms of manganese toxicity:

1. The appearance of yellowish-brown spots on the veins of the leaf.
2. The chloroplasts become devoid of chlorophylls due to manganese toxicity.
3. Necrosis on interveinal areas of leaves.