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Abstract Detail


Millan, Pamela [1], Melcher, Peter [1], Sack, Lawren [2].

Intracanopy leaf plasticity and the impact of light versus height on carbon and nitrogen isotope discrimination for five temperate deciduous tree species.

The goal of this study was to determine how intracanopy microclimate impacts leaf-level traits. Many leaf traits are known to vary within canopies, such as leaf thickness, leaf area, stomatal conductance and leaf water status, and this suggests potentially strong variation in leaf nutrient composition and carbon isotope discrimination (Δ). We determined the impact of light and height on Δ, nitrogen (N) and carbon (C) concentrations as well as other anatomical and morphological leaf traits. We collected leaves using an aerial lift from three crown positions, top-exposed (TE), basal-exposed (BE), and basal-interior (BI) from five common mature temperate tree species. The Δ related to both height and light with light having a stronger signal in Δ than height for Betula alleghaniensis (birch), Ginkgo biloba (ginkgo) and Quercus rubra (red oak),and height having a stronger signal on Δ for Liriodendron tulipifera (tuliptree) and Sassifras albidum (sassafras). We also found correlations of carbon and nitrogen concentrations measured on a leaf area basis with canopy irradiance and height (r =0.51-0.73, 0.29-0.33 and 0.50-0.73 respectively; P < 0.05). However, when analyzed on a leaf mass basis the N and Cconcentrations and N:C ratios were independent of irradiance and height (r =0.009-0.16; P >0.10). These relationships were supported using an Akaike Information Criterion (AIC) analysis of models indicating that both irradiance and height played an important role in determining Δ; a model based on both factors was selected above models based on either factor alone. By contrast, for Carea,a model based on height alone was selected and for Narea, the model based on irradiance alone was selected. This variation indicates species-differences in the modulation of carbon uptake and water loss across the canopy.

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1 - Ithaca College, Biology, 953 Danby Road, Center for Natural Sciences, Ithaca, NY, 14850, United States
2 - UCLA, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA

carbon isotope
leaf development.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Khorassan Ballroom/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 5:30 PM
Number: PEP003
Abstract ID:642

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