Manganese

Importance of Manganese

• Manganese is involved in pollen germination, pollen tube growth, root cell elongation and resistance to root pathogens
• It also plays a role in chloroplast formation, photosynthesis, nitrogen metabolism and synthesis of some enzymes

Manganese deficiency symptoms

Typical leaf symptoms of Mn deficiency first develop in young leaves of a plant, this is because of its high immobility in plants. It appears as interveinal chlorosis (yellow leaves with green veins) on the young leaves, and sometimes tan, sunken spots that appear in the chlorotic areas between the veins. Manganese deficiency or toxicity is often mistaken for iron deficiency or toxicity.

Common causes of Manganese deficiency

• Manganese deficiency can occur when the soil pH exceeds 6.5, because it is tied up and unavailable for uptake.
• Excessive leaching or applying too many iron chelate drenches.

Manganese Toxicity

Manganese toxicity symptoms begin with the burning of the tips and margins of older leaves or as reddish-brown spots across older leaves. Severe toxicity may result in spots becoming more numerous and larger, forming patches on the older leaves. At pH levels below 5.5, manganese is very soluble and toxicity symptoms are probable.

Similarities of Manganese to Iron

Manganese and iron have similar visual deficiency and toxicity symptoms. Manganese and iron deficiencies both appear as interveinal chlorosis of young leaves. The major difference is that as manganese deficiency progresses, tan areas develop between the veins while iron deficiency progresses toward an almost white appearance in the leaves.