The main function of copper in plant metabolism is as an activator or component of enzymes that participate in oxidation-reduction reactions.
Plant resistance to fungal diseases is also related to an adequate supply of copper. It increases drought resistance and is important in the formation of knots.
Deficiency – Green spots appear on the leaves, these can become discolored, become thin and can be curled when the deficiency is severe. The culms and meristems lose their turgidity (‘fallen top’ disease) and acquire an appearance similar to a crushed clump. Reduction of tillering and drop in productivity.