Comparison of phenolic compounds from galls and shoots of Picea glauca

The influence of the gall aphid Adelges abietis on the metabolism of phenolic compounds was studied by comparing extracts of-spruce shoots and galls of the same tree during one vegetation period. Phenolics and phenolic glucosides, 47 in total, were identified and quantified as their trimethylsilylated derivatives by CC-mass spectrometry. Shoots contained two to ten times more free phenolics than galls. Their amount increased over the vegetation period. The main compounds, beside cinnamic acids, were acetophenone derivatives in shoots and 4-hydroxyphenylpropionic acid in galls. The amount of phenolic glucosides in shoots exceeded that in galls by a factor of 60 to 100. Shoots contained preferentially acetophenone glucosides. Derivatives of cinnamic alcohol glucosides prevailed in galls. An accumulation of lignans and a decrease of cinnamic alcohol glucosides started in galls when larvae began hatching. In shoots lignans were present only in small amounts. Copyright (C) 1996 Elsevier Science Ltd