ABSTRACT
Potassium and chlorine, both monovalent ions, are also essential elements in plants, which participate as cofactor of many enzymes and it is involved in the oxygen evolution during the photosynthetic reactions, respectively. The plants respond to an inadequate supply of an essential element by showing symptoms of deficiency characteristics and could have its effect on several parts of a plant. The symptoms of deficiency vary from one element to another. The plant part in which a deficiency symptom occurs depends mainly on two factors: the function or functions of the element in the plant and the mobility of the elements from older plant tissue structures to younger structures. A good example that highlights both factors explained above is the chlorosis as a result of the deficiency of magnesium. Besides, the chlorosis of older leaves occurs in the lower part of the plant comes more severe than in younger leaves.
