Neilson, Elizabeth H , Goodger, Jason QD , Woodrow, Ian E .
Novel aspects of cyanogenesis in Eucalyptus camphora subsp. humeana.
Cyanogenesis is the release of cyanide from certain organisms upon tissue disruption. Tissue disruption, such as that caused by herbivory, brings cyanogenic glycosides into contact with catabolic enzymes and toxic HCN is subsequently released. Thereby the process provides a measure of defense especially against generalist herbivores and pathogens. Within the Australian genus Eucalyptus, a number of species have been identified as being cyanogenic, and here we describe E. camphora subsp. humeana as a new and highly unique addition to this group. We found that adult foliage contains at least five different cyanogenic glycosides, three of which were purified and identified (prunasin, sambunigrin and amygdalin). The co-occurrence of multiple cyanogenic glycosides within a single plant tissue type is rare, and E. camphora is particularly unique as the presence of at least five foliar cyanogenic glycosides has never been recorded for any cyanogenic species. Two natural populations of E. camphora trees were screened for cyanogenesis, and quantitative polymorphism was measured at both sites. A progeny trial, tracking cyanogenic glycoside concentration through ontogeny, was performed on 60 different E. camphora seedlings. Interestingly, all seedlings exhibit very low cyanogenic glycoside concentrations, which increase throughout plant ontogeny. Furthermore, initiation of cyanogenic glycoside production occurs relatively late in plant development, with all plants undergoing an acyanogenic to cyanogenic transition. Eucalyptus camphora is relatively unique among cyanogenic trees having multiple foliar cyanogenic glycosides and an apparently marked ontogenetic regulation of cyanogenic capacity.
Log in to add this item to your schedule
1 - The University of Melbourne, School of Botany, Parkville, Vic, 3010, Australia
2 - The University of Melbourne, School of Botany
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM