The importance of copper (Cu): It acts in the activation of photosynthesis and respiration enzymes. It acts in the distribution of carbohydrates, acts in the reduction and fixation of the N of the FBN (Biological nitrogen fixation). Helps in resistance to fungal diseases.
Copper (Cu) deficiency usually causes necrosis at the leaflet tips of young leaves. This necrosis continues along the edges of the leaflets, resulting in leaves that appear to have lost turgidity and water, and appear to have dried up.
Growth is retarded and the plant’s color changes to gray-green, blue-green, or olive. For many plant species, high amounts of copper in nutrient solution are toxic and limit growth.