Function of manganese in plants
Manganese photosynthetic enzyme activity, are involved in respiration and nitrogen metabolism. The functions of manganese are thought to be closely related to the functions of iron, as well as to the formation of chlorophyll. For this reason, jaundice is a common symptom when manganese is deficient. Manganese reduces the solubility of iron through oxidation, and for this reason, the presence of large amounts of manganese in the plant leads to iron deficiency and yellowness. There is a close relationship between soil pH and manganese availability. The availability of manganese is low in soils with high pH. For this reason, Manganese deficiency is common in calcareous soils.
Manganese deficiency in plants
It is often confused with Iron Deficiency. Correct diagnosis can be made with foliar analysis. Deficiencies in young leaves appear as green vein networks on a light green background resembling iron deficiency. In advanced stages, the light green parts turn white and the leaves fall off. Brownish, black or greenish spots may appear adjacent to the veins. Plants usually show deficiency symptoms in neutral and alkaline soils. In highly acidic soils, it is possible to intake manganese enough to cause toxicity to the plant.
It also has a similarity to the symptoms of magnesium deficiency. Symptoms begin with chlorosis occurring between the main veins starting from the leaf edge and extending towards the main vein. But it does not resemble magnesium deficiency, yellowness is normally limited to the leaf edges in manganese deficiency and yellowness rarely develops between the veins. Another distinctive feature is that manganese deficiency is first seen in young leaves and fine leaf veins do not remain green as seen in iron deficiency. In manganese deficiency, yellow spots appear on the leaves in addition to the inter-leaf chlorosis.