Symptoms
Symptoms of manganese deficiency start on younger leaves. With a slight deficiency, the leaves show a light green colour without any specific symptoms. Later, when deficiency becomes more severe, chlorosis appears in the intercostal zones at the leaf margins. These chloroses become necrotic and the leaf margins are curled downwards. Leaf tips show the symptoms first.
Reasons
Manganese deficiency
Magnesium deficiency also leads to chlorotic zones which later become necrotic, but these start on older leaves.
Iron deficiency symptoms also start on younger leaves, but the chlorosis affects the whole leaf and necrosis does not occur.
Manganese deficiency made worse by
Organic soils
Sandy soils
High pH
Cold wet periods
Fluffy soils
Manganese is important for
Respiration, N-metabolism and chlorophyll synthesis