Differentiate between micronutrients and macronutrients of plants.

The roots of green plants absorb a large number of elements from the soil. Some of these elements are absolutely necessary for normal growth and development of the plant. These elements, said to be macronutrients, are potassium, calcium, magnesium, iron, carbon, hydrogen, oxygen, nitrogen, sulphur and phosphorus. Macronutrients must be present in plant tissues in concentration of at least one milligram per gram of dry matter. There are other elements which are specifically required by the plant in very minute quantities, and these elements are known as micronutrients. Manganese, copper, molybdenum, zinc and boron are essential micronutrients.