Nutrients that are required in large quantities by plants are called macromolecules. The number of macromolecules is 9. Nutrients in amounts of 1-10 mg or more per gram of weight are called macronutrients. Macro elements are oxygen, carbon, hydrogen, phosphorus, sulphur, nitrogen, magnesium, potassium and calcium. Among them, except for carbon, hydrogen and oxygen, the remaining 6 elements are absorbed by plants from the soil. Magnesium forms chlorophyll and chlorophyll causes photosynthesis. A lack of phosphorus causes the leaves, flowers and fruits of plants to fall off. Silicon macromolecules (quantity-30) for grass plants.