Abstract of a paper based on work funded in part by the Australian Flora Foundation

Constitutive polymorphic cyanogenesis in the Australian rainforest tree, Ryparosa kurrangii (Achariaceae)
Bruce L. Webber, Rebecca E. Miller, Ian E. Woodrow
School of Botany, The University of Melbourne, Victoria 3010, Australia
Phytochemistry 68 (2007) 2068–2074

Abstract
Cyanogenesis, the liberation of volatile hydrogen cyanide from endogenous cyanide-containing compounds, is a proven plant defence mechanism and the particular cyanogens involved have taxonomic utility. The cyclopentenoncyanhydrin glycoside gynocardin was the only cyanogen isolated from foliar tissue of the rare Australian rainforest tree, Ryparosa kurrangii (Achariaceae). Mechanical damage simulating foliar herbivory did not induce a significant increase in the expression of cyanogenesis over a 24 h period, indicating cyanogenic herbivore defence in R. kurrangii is constitutive. The cyanogenic potential of mature leaves was quantitatively polymorphic between trees in a natural population, ranging from 0.54 to 4.77 mg CN /g dry wt leaf tissue.
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