magnesium

Symbol: Mg. A metal element, atomic number 12, atomic weight 24.3, important as a macronutrient for plant growth. It forms part of the chlorophyll molecule and deficiency thus leads to chlorosis. It is also a cofactor for phosphotransferase and phosphohydrolase enzymes. Other symptoms of magnesium deficiency are necrosis, stunted growth, and in some plants a puckering and whitening of the leaves at the edges. Magnesium is added to soil as magnesium sulphate or magnesium oxide.