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Abstract Detail


Photosynthesis(Carbon)

Naithani, Kusum [1], Ewers, Brent [2], Pendall, Elise [2].

Quantifying stomatal and non-stomatal limitation to carbon assimilation during succession in a sagebrush ecosystem.

Shrubland ecosystems represent a potentially dynamic but poorly understood component of the global carbon cycle. Shrubland ecosystems play an important role in the hydrology of the inter-mountain basins of the United Sates. Our objective was to quantify stomatal and non-stomatal limitation to carbon assimilation resulting from stand age and water availability in a sagebrush burn chronosequence. Gas exchange techniques were used to investigate light-saturated carbon assimilation and stomatal and non-stomatal limitations to photo of three dominant species, Artemisia tridentata var vaseyana (mountain big sagebrush), Lupinus argentus (lupine) and Elymus smithii (western wheatgrass) across a prescribed burn chronosequence. The measurements were conducted on three stands ranging in age from 3 to 39 years near the Sierra Madre Mountains, Wyoming, USA. Our results show that rate of electron transport and net photosynthesis decreased with increasing age in all three plant species. Stomatal and non-stomatal contributions to decreases in assimilation resulting from stand age and drought were quantified relative to the maximum rates obtained early in the season at optimal soil water contents. Lupine and western wheatgrass had greater net photosynthesis than sagebrush under high water availability but were less drought tolerant. Estimating seasonal limitations under natural conditions, as shown in this study, provides a useful basis for comparing limitation processes between years and species. Quantifying stomatal and nonstomatal limitation to carbon assimilation increases mechanistic understanding of responses of carbon and water fluxes to disturbance and drought in shrubland ecosystems.


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Related Links:
USDA University of Wyoming Sagebrush Project


1 - University of Wyoming, Department of Botany, 3165, 1000 E University Ave, Laramie, Wyoming, 82071, USA
2 - University of Wyoming, Department of Botany

Keywords:
gas exchange
chlorophyll fluorescence
Artemisia tridentata var vaseyana
Lupinus argentus
Elymus smithii.

Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P13013
Abstract ID:1967


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