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- Title
Temporal variability of phenolics and batatasin-III in Empetrum hermaphroditum leaves over an eight-year period: interpretation of ecological function
- Authors
Nilsson, M.-C.; Gallet, C.; Wallstedt, A.
- Abstract
Although many plant species produce high levels of secondary metabolites, comparatively little is known about the temporal variability ofthe production and concentrations of these compounds, either in terms of quantitative or qualitative aspects. In the Swedish boreal forest the dwarf-shrub species Empetrum hermaphroditum produces high levels of phenolics which are important agents of allelopathy, regulators of herbivory and determinants of plant litter decomposition. We performed quantitative analyses of total phenolics and monitored the phytotoxic activity (defined as the ability of the extracts to retard germination of Populus tremula seeds) of aqueous leaf extracts from threeage classes of leaves, collected from the field approximately every two weeks for every growing season from 1988 to 1995. The concentrations of the dihydrostilbene batatasin-III, an E. hermaphrodium metabolite with a documented phytotoxic effect, were determined in both extracts and entire leaves for material collected in 1988 and 1994. We also studied leaf gland variation of first-year leaves in relation to phenolic concentration and phytotoxic activity. Large differences existed between sampling times within years, with first-year shoots producing high levels of phenolics; these levels were maintained for second-year shoots but phenolic concentrations declined for third-year shoots, i.e. prior to leaf senescence. Phytotoxic activity was low immediately after leaf emergence, and was not consistently correlated to total phenolic concentrations of the leaves. However, more detailed analyses showed that much of the phytotoxic activity of E. hermaphrodium extracts is due to the production of batatasin-III, which reaches its maximum concentration not until September of the first year. We believe that batatasin-III is critical in determining the phytotoxic effects of E. hermaphrodium and that this compound may have additional benefits for E. hermaphrodium other than deterring herbivory. Leaf glan
- Subjects
PLANT species; PHYTOTOXICITY
- Publication
Oikos, 1998, Vol 81, Issue 1, p6
- ISSN
0030-1299
- Publication type
Article
- DOI
10.2307/3546462