Indole-3-acetic acid

Structural formula
General
Surname	Indole-3-acetic acid
other names	Heteroauxin; Rhizopine; Indol-3-ylacetic acid ( IUPAC ); INDOLE ACETIC ACID ( INCI ) ;
Molecular formula	C 10 H 9 NO 2
Brief description	colorless flakes or crystalline powder
External identifiers / databases
EC number	201-748-2
ECHA InfoCard	100.001.590
PubChem	802
ChemSpider	780
DrugBank	DB07950
Wikidata	Q411208
properties
Molar mass	175.18 g mol −1
Physical state	firmly
Melting point	166 ° C
pK s value	4.75
solubility	slightly soluble in water (1.5 g l −1 at 20 ° C); soluble in acetone and ether; easily soluble in alcohol;
safety instructions
GHS labeling of hazardous substances	no GHS pictograms
	no GHS pictograms
H and P phrases	H: no H-phrases
	P: no P-phrases
Toxicological data	> 500 mg kg −1 ( LD 50 , mouse , oral )
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Indole-3-acetic acid ( IES or IAA , from English indole-3-acetic acid ) is a naturally occurring phytohormone from the auxins group . It is mainly formed in the primary meristems of the plants and then actively transported to the sites of action. The first bioassays with phytohormones were carried out with IAA .

Biological effect

The light-sensitive indole-3-acetic acid has a stimulating effect on the growth of plants and their roots even in the smallest amounts. The maize root reacts to a concentration of 10 ⁻¹² g · l ⁻¹ . If the concentration of indole-3-acetic acid is too high, the synthesis of abscisic acid is promoted, a stress “hormone” which, for example, has a negative effect on the growth in length of the roots.

use

Indole-3-acetic acid is a component of numerous preparations (e.g. fertilizer solutions, boosters) that control plant and root growth. In addition to other auxins, the cheaper synthetic 1-naphthylacetic acid (NAA, English for 1-naphthylacetic acid ) or other structural analogues are often used.

Chemically modified derivatives are used in high doses partly as herbicides due to their growth-inhibiting effect at higher concentrations.

proof

Indole-3-acetic acid can be detected using the Salkowski reagent.

The reliable qualitative and quantitative determination in urine samples is achieved through the use of lipophilic gel chromatography on Sephadex LH 20 and subsequent gas chromatography of the trimethylsilyl derivatives.

Individual evidence

↑ Entry on INDOLE ACETIC ACID in the CosIng database of the EU Commission, accessed on June 30, 2020.
↑ ^a ^b ^c ^d ^e Entry on 1H-indol-3-ylacetic acid. In: Römpp Online . Georg Thieme Verlag, accessed on June 20, 2014.
↑ ^a ^b ^c Entry on indole-3-acetic acid in the ChemIDplus database of the United States National Library of Medicine (NLM) .
↑ ^a ^b Data sheet 3-Indoleacetic acid, 98% from Sigma-Aldrich , accessed on February 17, 2013 ( PDF ).
↑ U. Kutschera : Principles of plant physiology. 2nd Edition. Spectrum Academic Publishing House, Heidelberg / Berlin 2002.
^ SJ Nissen, EG Sutter: Stability of IAA and IBA in nutrient medium to several tissue culture procedures. In: HortScience. 25, 1990, pp. 800-802.
^ JD Goeschl, L. Rappaport, HK Pratt: Ethylene as a factor regulating the growth of pea epicotyls subjected to physical stress. In: Plant Physiol. 41, 1966, pp. 877-884.
↑ E. Glickmann, Y. Dessaux: A critical examination of the specificity of the salkowski reagent for indolic compounds produced by phytopatogenic bacteria. In: Appl. Environ. Microbiol. 61, 1995, pp. 793-796.
↑ HU Melchert, H. Hoffmeister: Determination of the urinary metabolites hydroxyindole-acetic acid, vanillyl mandelic acid and homovanillic acid by means of lipophilic gel chromatography and gas chromatography. In: J Clin Chem Clin Biochem. 15 (2), Feb 1977, pp. 81-87, German. PMID 845547 .

Web links

Commons : Indole acetic acid - Collection of images, videos and audio files

Wiktionary: Indole-3-acetic acid - explanations of meanings, word origins, synonyms, translations

[CosIng-1] Entry on INDOLE ACETIC ACID in the CosIng database of the EU Commission, accessed on June 30, 2020.

[Römpp-2] Entry on 1H-indol-3-ylacetic acid. In: Römpp Online . Georg Thieme Verlag, accessed on June 20, 2014.

[ChemIDplus-3] Entry on indole-3-acetic acid in the ChemIDplus database of the United States National Library of Medicine (NLM) .

[Sigma-4] Data sheet 3-Indoleacetic acid, 98% from Sigma-Aldrich , accessed on February 17, 2013 ( PDF ).

[5] U. Kutschera : Principles of plant physiology. 2nd Edition. Spectrum Academic Publishing House, Heidelberg / Berlin 2002.

[6] SJ Nissen, EG Sutter: Stability of IAA and IBA in nutrient medium to several tissue culture procedures. In: HortScience. 25, 1990, pp. 800-802.

[7] JD Goeschl, L. Rappaport, HK Pratt: Ethylene as a factor regulating the growth of pea epicotyls subjected to physical stress. In: Plant Physiol. 41, 1966, pp. 877-884.

[8] E. Glickmann, Y. Dessaux: A critical examination of the specificity of the salkowski reagent for indolic compounds produced by phytopatogenic bacteria. In: Appl. Environ. Microbiol. 61, 1995, pp. 793-796.

[9] HU Melchert, H. Hoffmeister: Determination of the urinary metabolites hydroxyindole-acetic acid, vanillyl mandelic acid and homovanillic acid by means of lipophilic gel chromatography and gas chromatography. In: J Clin Chem Clin Biochem. 15 (2), Feb 1977, pp. 81-87, German. PMID 845547 .