manganese

Symbol: Mn. A metallic element, atomic number 25, atomic weight 54.94, needed in trace amounts by plants for successful growth. Manganese ions are required as cofactors by certain enzymes, e.g. kinases and IAA oxidase. Certain deficiency diseases, e.g. blight of sugar cane and grey speck of oats, are attributed to manganese deficiency. More general symptoms include dwarfing and mottling of the upper leaves. Manganese is often added to the soil as manganous sulphate to treat such problems.