Zinc is essential for the biosynthesis of:
IAA or indole-3-acetic acid is the principal natural auxin which occurs in all plants. Its primary function is to promote growth. The biosynthesis of auxin (IAA) occurs mainly from an amino acid tryptophan. Zinc is an essential element for auxin biosynthesis. When plants are made to grow in zinc-deficient conditions, they fail to grow and elongate due to low auxin concentration. This proves the importance of zinc in the biosynthesis of auxins.