Volatile Components From the Roots of Acacia pulchella R.br. And Their Effect on Phytophthora cinnamomi Rands

Abstract

A steam-volatile extractive of the roots of Acacia pulchella has been shown to inhibit the growth of the pathogenic fungus Phytophthora cinnamomi. The extractive restricted mycelial growth, suppressed sporangial production and germination and reduced zoospore germination of the fungus when grown axenically. Examination by gas chromatography of the headspace vapours of whole roots indicated the presence of 270 organic components. Of these, 78 components were identified and an additional 56 tentatively identified by combined gas chromatography and mass spectrometry. The major volatile compounds identified were 2- and 3-methylbutanol, hexanol, pentanal, 2- and 3-methylbutanal, 4- methylacetophenone and carbon disulfide. The antifungal activity of the root volatiles and the resistance of A . Pulchella to invasion by P. cinnamomi are discussed.