- Indole-3-acetic acid
Section1= Chembox Identifiers
ChemSpiderID = 780
Section2= Chembox Properties
MeltingPt=168-170 °C (441-443 K)
Section3= Chembox Hazards
Indole-3-acetic acid, also known as IAA, is a member of the group of
phytohormones called auxins. IAA is generally considered to be the most important native auxin.
It is produced in cells in the
apex( bud) and young leaves of a plant. Plant cells synthesize IAA from tryptophan. It has many different effects, as all auxins do, such as inducing cell elongation and cell divisionwith all subsequent results for plant growth and development.There are less expensive and metabolically stable synthetic auxinanalogs on the market for use in horticulture, such as indole-3-butyric acid(IBA) and 1-naphthaleneacetic acid (NAA).
Studies of IAA in the 1940s led to the development of the
phenoxy herbicides 2,4-dichlorophenoxyacetic acid(2,4-D) and 2,4,5-trichlorophenoxyacetic acid(2,4,5-T). Like IBA and NAA, 2,4-D and 2,4,5-T are metabolically and environmentally more stable analogs of IAA. However, when sprayed on broad-leaf dicot plants, they induce rapid, uncontrolled growth, eventually killing them. First introduced in 1946, these herbicides were in widespread use in agricultureby the middle of the 1950s.
Chemical properties of IAA
IAA can be produced by the reaction of
indolewith potassium glycolate at 250 C, but this compound is chemically unstable in particular when exposed to light or changing temperature.
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