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Consequences of elevated carbon dioxide and ozone for foliar chemical composition and dynamics in trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera)
- Source :
- Environmental Pollution; Dec2001, Vol. 115 Issue 3, p395, 0p
- Publication Year :
- 2001
-
Abstract
- Atmospheric chemical composition affects foliar chemical composition, which in turn influences the dynamics of both herbivory and decomposition in ecosystems. We assessed the independent and interactive effects of CO<subscript>2</subscript> and O<subscript>3</subscript> fumigation on foliar chemistry of quaking aspen (Populus tremuloides) and paper birch (Betula papyrifera) at a Free-Air CO<subscript>2</subscript> Enrichment (FACE) facility in northern Wisconsin. Leaf samples were collected at five time periods during a single growing season, and analyzed for nitrogen, starch and condensed tannin concentrations, nitrogen resorption efficiencies (NREs), and C:N ratios. Enriched CO<subscript>2</subscript> reduced foliar nitrogen concentrations in aspen and birch; O<subscript>3</subscript> only marginally reduced nitrogen concentrations. NREs were unaffected by pollution treatment in aspen, declined with O<subscript>3</subscript> exposure in birch, and thisdecline was ameliorated by enriched CO<subscript>2</subscript>. C:N ratios of abscised leaves increased in response to enriched CO<subscript>2</subscript> in both tree species. O<subscript>3</subscript> did not significantly alter C:N ratios in aspen, although values tended to be higher in +CO<subscript>2</subscript>+O<subscript>3</subscript> leaves. For birch, O<subscript>3</subscript> decreased C:N ratios underambient CO<subscript>2</subscript> and increased C:N ratios under elevated CO<subscript>2</subscript>. Thus, under the combined pollutants, the C:N ratios of both aspen and birch leaves were elevated above the averaged responses to the individual and independent trace gas treatments. Starch concentrations were largely unresponsive to CO<subscript>2</subscript> and O<subscript>3</subscript>treatments in aspen, but increased in response to elevated CO<subscript>2</subscript> in birch. Levels of condensed tannins were negligibly affected by CO<subscript>2</subscript> and O<subscript>3</subscript> treatments in aspen, but increased in response to enriched CO<subscript>2</subscript> in birch. Results from this work suggest that changes in foliar chemical composition elicited by enriched CO<subscript>2</subscript> are likely to impact herbivory and decomposition [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02697491
- Volume :
- 115
- Issue :
- 3
- Database :
- Supplemental Index
- Journal :
- Environmental Pollution
- Publication Type :
- Academic Journal
- Accession number :
- 8290912