Submitted to: American Journal of Plant Sciences
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/14/2011
Publication Date: 2/1/2012
Citation: Bunce, J.A. 2012. Elevated carbon dioxide alters the relative fitness of Taraxacum officinale genotypes. American Journal of Plant Sciences. 3:202-208. Interpretive Summary: The concentration of carbon dioxide in the atmosphere continues to rise rapidly, and is known to directly affect the growth of crops and weeds. Traits which adapt plants to elevated concentrations of carbon dioxide are not known, and this lack of knowledge slows the deliberate adaptation of crops to global change. In this experiment we found that dandelion plants best adapted to elevated carbon dioxide concentrations had more rapid rates of leaf initiation and faster biomass production, but that these traits were not apparent when these plants were grown at current carbon dioxide concentrations. This work will be of interest to weed biologists and to crop scientists attempting to adapt crops to global changes.
Technical Abstract: I tested whether elevated carbon dioxide concentration differentially affected which genotypes of the apomictic species dandelion produced the largest number of viable seeds in two different field experiments, and identified morphological and physiological traits associated with fitness at elevated carbon dioxide. In one experiment, dandelions which persisted as weeds and were producing seeds three years after the establishment of alfalfa plots in open top chambers at ambient and elevated carbon dioxide were compared. In a second experiment, dandelion seeds collected from four diverse local habitats were mixed and scattered on bare soil in open top chambers at ambient and elevated carbon dioxide, and plants producing viable seeds one and two years after seeding were compared. In both experiments seeds produced in each chamber were collected, and many plants from the seed lot from each chamber were grown in controlled environment chambers to test whether the carbon dioxide concentration of the chamber of origin affected the mean value of various morphological and physiological parameters. In both experiments, the results indicated that field exposure to elevated carbon dioxide altered the relative fitness of genotypes. In both experiments, elevated carbon dioxide favored genotypes with more rapid leaf initiation, and which produced biomass more rapidly at elevated carbon dioxide. Traits adapting genotypes to elevated carbon dioxide were not evident when plants were grown at lower carbon dioxide. Overall, the results suggest that genotypes of this species vary widely in fitness at elevated carbon dioxide whether grown in monocultures or in mixed communities, and that this species could adapt rapidly to rising atmospheric carbon dioxide.