Ref ID: 10941
Ref Type: Journal
Authors: O'Reilly-Wapstra, J. M., Potts, B. M., McArthur, C., and Davies, N. W.
Pub Date: 2005
Journal Name: Oecologia
Volume: 142
Issue: 4
Start Page: 597
End Page: 605
ISBN/ISSN:
Keywords: blue gum/browser/browsing/chemistry/concentration/contrast/effect/environment/eucalypt/Eucalyptus/Eucalyptus globulus/expression/feeding/fertiliser/foliage/genetic/genetic variation/genotype/globulus/gum/herbivore/interaction/metabolite/nitrogen/nutrient/oil/pattern/plant/population/possum/resistance/secondary metabolite/seedling/seedlings/species/study/tannin/Tasmania/trial/Trichosurus vulpecula/variability/variation
Abstract: Plant resistance to herbivores can be influenced not only by the independent effects of plant genotype and environmental variation, but by interactions between the two. The main aim of this study was to assess the effects of environmental variability (nutrient treatment) on the known genetic based expression of resistance and defensive chemistry of Eucalyptus globulus to browsing by the generalist mammalian herbivore Trichosurus vulpecula. In a captive feeding trial, we measured intake of seedlings from one relatively resistant (Blue Gum Hill) and one relatively susceptible (St Helens) population of E. globulus grown under two nutrient treatments (no fertiliser, plus fertiliser). There was a significant genotype x fertiliser interaction effect on intake of E. globulus foliage by T. vulpecula, and the predicted genetic based resistance of the two populations was expressed only for the non fertilised treatment. Patterns of resistance largely reflected the combined and inverse effects of nitrogen and condensed tannin concentrations. The expression of plant secondary metabolite concentration differed between compounds, but in all cases the effects of plant genotype and fertiliser treatment were independent. The formylated phloroglucinol compounds differed significantly between genotypes but not between fertiliser treatments. In contrast, the effect of plant genotype on the expression of condensed tannins was weak but they were significantly reduced by fertiliser. Essential oils were influenced by both plant genotype and fertiliser treatment and were significantly higher in the fertilised seedlings than in the non-fertilised seedlings. This study highlights interactive effects of plant genotype and environment in influencing the phenotypic expression of resistance in a eucalypt species to a mammalian browser. It also demonstrates that this interactive effect is the net result of independent effects of genotype and environment on plant chemistry and finally, that different groups of compounds within a plant can respond very differently to variation in environmental conditions
Notes: Entered by Julianne O'Reilly-Wapstra (25/08/2004)
Reprint: Not in File
Program: SPF Resource Protection
Project: C3; C3
Deliverable: C3-1; C3-1
Confidentiality: Confidential to All Partners until Published
Availability: Authors
Report: Annual Report 2004/5
Type: Article
Address: joreilly@utas.edu.au