Induced ovulation

Indoleacetic acid (IAA) is the most common, naturally occurring, plant hormone of the auxin class. It is the best known of the auxins, and has been the subject of extensive studies by plant physiologists. IAA is a derivative of indole, featuring a carboxymethyl substituent. It is a colorless solid that is soluble in organic solvents.

Chemistry

IAA is a derivative of indole, with a carboxymethyl group (CH2COOH) replacing hydrogen of the heterocyclic 5-membered ring. The molecule is categorized as an alkaloid.

Biosynthesis

IAA is predominantly produced in cells of the apex (bud) and very young leaves of a plant. Plants can synthesize IAA by several independent biosynthetic pathways. Four known pathways are:

• The indole-3-glycerol phosphate pathway
• The indole-3-pyruvic acid pathway
• The indole-3-acetonitrile pathway
• The tryptamine pathway

Function

IAA induces cell elongation and cell division and also has a role in phototropism and gravitropism. It also promotes the formation of roots in cuttings.

See also

• Auxin
• Plant hormone
• Tryptophan
• Phototropism
• Gravitropism

References

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