The impact of nitrogen fixation on soybean-herbivore interactions under elevated carbon dioxide

Project Overview
Project Abstract: 
Future increases in concentrations of atmospheric carbon dioxide due to anthropogenic activity will alter the dynamics of plant-herbivore interactions. Under elevated CO2, plants photosynthesize more, and as a result experience decreased foliar nitrogen concentration and an increased carbon: nitrogen ratio. Thus, nutritional quality of plant tissue decreases, carbon-based constitutive defenses increase and nitrogen-based constitutive defenses decrease in non-legume C3 plants. Legumes, which have the ability to fix nitrogen, may be an exception to these rules. In this experiment, nodulating and non-nodulating strains of soybean are used to directly test whether N-fixation buffers the legume Glycine max (soybean) against the adverse effects of elevated CO2. Soybean was grown for four weeks in chambers under elevated and ambient CO2. N content, C:N ratio and constitutive and induced levels of the defense compounds genistein, rutin, quercetin and coumestrol were then measured.
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