Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 2/6/2002
Publication Date: N/A
Technical Abstract: Although rising atmospheric carbon dioxide is known to stimulate photosynthesis and growth in crop plants, less work has determined the extent to which CO2 will alter the growth, morphology and gas exchange of noxious weedy species. Using controlled environment chambers to stimulate past, present and future CO2 concentrations, we examined the response of six known noxious weeds; yellow starthistle (Centaurea solstitialis), perennial sowthistle (Sonchus arvensis), spotted knapweed (Centaurea maculosa), leaf spurge (Euphorbia esla), field bindweed (Convolvulus arvensis) and Canada thistle (Cirsium arvense) in order to determine the role of rising CO2 in the early growth of these species. On average weedy growth increased about 110 percent from pre-industrial to current CO2 concentrations, with the greatest growth stimulation occurring since the CO2 concentration of the 1950s. Future CO2 concentrations significantly increased growth compared to current ambient, but the overall increase was less (45 percent) than that observed for pre-industrial levels. Overall, stimulation of growth in response to pre-industrial CO2 was significantly higher than that reported for crop species, suggesting the possibility that recent increases in atmospheric CO2 during the 20th century may have been one factor in the spread of these invasive species.