engleski

Effect of 4-substitution on IAA's biological activity and physical properties

Pea (Pisum sativum L.) fruit naturally contain the auxins 4-Cl-IAA and IAA, but only 4-Cl-IAA can substitute for seeds in maintaining pea fruit growth in planta [Phytochemistry (1995) 40: 1361]. The biological and structural importance of the chemical substitution at the indole ring 4 position was tested by comparing IAA and 4-Cl-IAA with the synthetic auxins 4-F-IAA, 4-Me-IAA and 4-Et-IAA. The growth-promoting acitivities of the substituted auxins on pea pericarp in planta were 4-Cl-IAA>4-Me-IAA>4-Et-IAA with IAA and 4-F-IAA not promoting growth. The substituents affected the physico-chemical properties of the compounds (lipophilicity and acid-base properties of the indole NH). The lipophilicities of the 4-substituted IAAs (4-Et-IAA>4-Cl-IAA>4-Me-IAA>4-F-IAA>IAA) did not linearly correlate with growth activities. NMR chemical shift analysis showed that substitution at the 4 position influenced NH acidity as follows: 4-F-IAA>4-Cl-IAA>IAA=4-Et-IAA>4-Me-IAA.

Pisum sativum ; pea ; fruit development ; pericarp growth ; indole-3-acetic acid ; 4-chloroindole-3-acetic acid ; 4-fluoroindole-3-acetic acid ; 4-methylindole-3-acetic acid ; 4-ethylindole-3-acetic acid

Document Type:Meeting Abstract