Olsen, Jacob , Tetreault, Hannah , Goad, Rachel , Mendola, Meredith , Johnson, Loretta , Baer, Sara , Maricle, Brian .
Photosynthetic variation of big bluestem and sand bluestem influenced by ecotype and precipitation.
Big bluestem is a perennial, warm-season, C4 grass that dominates tallgrass prairies in North America. It has high variation of phenotypes among its ecotypes across the Great Plains. No attempt has been made previously to study ecotypes of big bluestem over a large precipitation gradient. Four ecotypes of big bluestem, including a common cultivar Kaw, and one ecotype of sand bluestem were reciprocally transplanted in four locations across the east-west precipitation gradient of the Great Plains. Source populations for the native ecotypes, collected from pristine prairies in central and eastern KS, and southern IL, were planted across the precipitation gradient (400 mm/yr to 1200 mm/yr) in Colby, Hays, and Manhattan, KS and Carbondale, IL. Photosynthetic measurements were taken on each plant during times early, middle, and late in the growing season. Sand bluestem exhibited photosynthetic rates 23% higher across sites than big bluestem, possibly through development of lower water potentials or through structural adaptations of leaves. The Hays ecotype exhibited photosynthetic rates 15% higher across all sites than Kaw, the closest rival of the big bluestem ecotypes, showing the Hays ecotype has adapted to dry conditions, but can take advantage of high rainfall when available. Differences between ecotypes became especially pronounced at drier sites, where putative drought adaptations of the Hays ecotype were particularly advantageous. The results of this project give knowledge on the potential fate of the Great Plains ecosystem in the face of impending climate change.
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1 - Fort Hays State University, Department of Biological Sciences
2 - Kansas State University, Division of Biology
3 - Southern Illinois University, Department of Plant Biology
4 - Fort Hays State University, Department of Biological Sciences, 600 Park Street, Hays, Kansas, 67601, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Forsyth Room/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 3:35 PM