Main function of plant nutrients are as given below

Nitrogen: Synthesis of proteins  in the plant. It is consumed by plants during growth, flowering and fruiting stages

Phosphorus: Phosphorus is used by plants for cell divisions and energy requirments

Potassium: Potassium is used by plants mainly Transports of sugar, stomata control, cofactor of many enzymes and disease resistance.

Calcium: A major building block of cell wall, reduces susceptibility to diseases

Sulphur: Synthesis of essential amino acids cystin and methionine.

Magnesium: central part of chlorophyll molecule

Iron: Chlorophyll synthesis

Manganese: Necessary in photosynthesis

Boron: Formation of cell wall, germination and elongation of pollen tube, participates in metabolism  and transport of sugars

Zinc: Auxins Synthesis

Copper: Influence in the metabolism of nitrogen and carbohydrates

Molybdenum: Component of Nitrate reductase and nitrogenase enzymes.