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Title: Cogongrass ecotypes respond differently to elevated atmospheric CO2

item Runion, George
item Prior, Stephen - Steve
item Torbert, Henry - Allen
item VAN SANTEN, EDZARD - Auburn University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/17/2015
Publication Date: 5/17/2015
Citation: Runion, G.B., Prior, S.A., Torbert III, H.A., Van Santen, E. 2015. Cogongrass ecotypes respond differently to elevated atmospheric CO2 (Abstract). Program Abstracts for the 47th Annual Air Pollution Workshop and Symposium. CDROM.

Interpretive Summary:

Technical Abstract: Cogongrass is listed as one of the top ten worst weeds in the world and is a major problem in the Southeast US. We investigated this invasive, C4 perennial grass, selecting five ecotypes (Florida, Hybrid, Louisiana, Mobile, and North Alabama) found in the Southeast, in addition to a red-leaved ornamental (‘Red Baron’) variety. All plants were container grown for six months in open top chambers under ambient and elevated (ambient plus 200 ppm) atmospheric CO2. Under high CO2 plants displayed greater height, carbon content, and photosynthesis. In addition, plants grown under high CO2 had lower tissue nitrogen concentration, but both nitrogen and water use efficiencies increased. These responses, in addition to an average dry weight increase of 10% are typical responses for grasses to elevated CO2. The ‘Red Baron’ and Mobile ecotypes showed no significant growth response to elevated CO2, while the hybrid ecotype exhibited the greatest growth (followed by Louisiana, North Alabama, and Florida ecotypes). Few treatment interactions for other measured variables were observed, but when significant, the same pattern was observed with the hybrid, Louisiana, Florida, and/or North Alabama ecotypes showing a positive response to CO2 and no response for ‘Red Baron’ and Mobile. Findings indicate that some cogongrass ecotypes will likely become more problematic in the southeastern U.S. with rising levels of atmospheric CO2.