Elements which are needed by plants for growth in a very small quantity is called micro element or trace element. Sodium, zinc, boron, etc. are some examples of the trace element.

Nitrogen is required by plants in a great amount as its constituent amino acids, nucleic acid, amides, proteins, nucleotides, and coenzymes.

Phosphorus deficiency in plants can lead to the formation of dead tissues in the leaves which is called necrotic spots and causes dark green color of leaves.

Deficiency of magnesium causes chlorosis in older leaves first while chlorosis in younger leaves is caused by the deficiency of sulfur.

Nitrogenase requires molybdenum for its activity while dehydrogenase, decarboxylases, and kinases require manganese forits efficient function.