Essential elements required in large quantities are called macro and those required in small quantities are called micronutrient. Essential elements are very much necessary for normal growth and reproduction of the plant, they participate directly in the metabolic reaction, and their deficiency results in deficiency symptoms. The important microelements are boron (B), chlorine (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), and zinc (Zn).