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Abstract Detail



Ecophysiology

Maricle, Brian [1], Caudle, Keri L. [2], Olsen, Jacob [1], Bryant, Johnny [3], de la Cruz, Angel [3], Jensen, Amber [4], Baer, Sara [5], Bello, Nora [6], Johnson, Loretta [7].

A possible mechanism for increased performance of a xeric adapted big bluestem (Andropogon gerardii) ecotype: Photosynthesis, nitrogen, and chlorophyll concentration of leaves in reciprocal gardens across the Great Plains.

Big bluestem (Andropogon gerardii) is a dominant C4 grass in tallgrass prairie. With wide variation in precipitation across the tallgrass prairie (400-1200 mm per year from western Kansas to southern Illinois), it is expected genetically-based ecotypic differences might occur, especially regarding adaptations to water availability. Photosynthesis, leaf chlorophyll concentration (based on SPAD measures), and leaf nitrogen concentration (%N) were measured in eight replicate blocks of twelve plants, representing three ecotypes of A. gerardii (from Central Kansas CKS, Eastern Kansas EKS, and southern Illinois SIL) at four reciprocal garden sites (Colby, Hays, and Manhattan, Kansas, and Carbondale, Illinois). Photosynthetic rates of the CKS ecotype were consistently greater than those of the EKS and SIL ecotypes in all planting sites. For N concentrations, %N of the CKS ecotype was greater than the SIL ecotype in all sites, yet %N of CKS was greater than EKS in Manhattan and Hays only. For chlorophyll concentrations (based on SPAD) during peak season, in the drier sites (i.e., Hays and Colby) the CKS ecotype was greater than the SIL and EKS ecotypes, but there were no ecotype differences in the Manhattan and Carbondale sites. Based on these results, we hypothesize increased N, manifested as higher chlorophyll and increased photosynthetic rates, confers advantage to the xeric Central Kansas ecotype, especially at the drier planting sites. This research helps to provide a mechanistic understanding of the observed ecotypic variation in physiological performance of big bluestem. Ultimately, this knowledge might help explain plant responses across a precipitation gradient in a dominant prairie species.


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1 - Fort Hays State University, Department Of Biological Sciences, 600 Park St., Hays, KS, 67601-4099, USA
2 - Fort Hays State University, Department of Biological Sciences, 600 Park St., Hays, KS, 67601, USA
3 - Kansas State University, Division of Biology, Manhattan, KS, 66506, USA
4 - Nebraska Wesleyan University, Lincoln, NE, 68504, USA
5 - Department of Plant Biology and Center for Ecology, Southern Illinois University, Carbondale, IL, 62901, USA
6 - Kansas State University, Department of Statistics, Manhattan, KS, 66506, USA
7 - Kansas State University, Biology, Ackert Hall Rm 232, Manhattan, KS, 66506-4901, USA

Keywords:
Photosynthesis
SPAD
nitrogen
ecotype
drought tolerance.

Presentation Type: Oral Paper:Papers for Topics
Session: 15
Location: Firs South/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 8:45 AM
Number: 15004
Abstract ID:555
Candidate for Awards:None


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