Zinc was one of the first micronutrients recognized as essential for plants. It plays a key role in many enzyme systems in plants. It controls the production of important growth regulators that influence new growth and development, thus one of the first indications of Zn deficiency is the presence of stunted plants resulting from a shortage of growth regulators.
Symptom Description — Zinc deficiency appears as a chlorosis in the interveinal areas of new leaves, producing a banding appearance. Leaf and plant growth become stunted with increasing severity of the deficiency and leaves eventually die and fall off the plant. At branch terminals of fruit and nut trees, rosetting occurs with considerable dieback of the branches.