
Form
Taken up as ionic Mn2+ and Mn3+, Manganese links with Iron to maintain photosynthesis and cell activity.
Function
Manganese regulates a wide range of reactions that occur within the cell. Often interchangeable with Iron, Manganese affects photosynthesis and is a vital part of both cell repair and defence. As a result, Manganese affects growth rates, plant development and tolerance to stress, particularly during the early stages of growth. Low Manganese status results in low plant vigour and reduced tolerance to stress and infection.

Early symptoms of interveinal chlorosis on young bean leaflet caused by manganese deficiency.
Symptoms
Low Manganese status affects younger leaves and active growing points. Plants display slow growth, lax canopy and low vigour. Young leaves show a distinct mottled interveinal chlorosis.
Significance
Manganese stress restricts the conversion of sunlight to plant energy, resulting in slow growth rates, poor development and low tolerance to both biotic and abiotic stress. Low Manganese status is often associated with alkaline soils and cold, wet growing conditions.

Manganese deficiency in grape, with mosaic-like disposed yellow area bounded by fine veins in interveinal areas.
Actions
Check soil status and root development for compaction. Seed treatment and routine foliar treatment can be very effective, especially during the early stages of plant development and times of stress.

A high concentration liquid suspension for low rate applications to avoid deficiency symptoms and increase yields.