Plant Responses to Increased Carbon Dioxide

Abstract

Rising atmospheric carbon dioxide (CO2) enhances carbon uptake in C3 plants and reduces stomatal conductance in C3 and C4 plants. Even though leaf N declines, RuBisCO activity increases so the photosynthetic rate rises as does photosynthetic N use efficiency. The responses show high variability, and while the magnitude of this "fertilization" effect appears to be confounded with experimental conditions. Growth of C3 plants increased by up to 25% and grain yield somewhat less. C3 plants are more responsive that C4 plants and legumes more responsive than grasses. Photosynthetic acclimation to high CO2 constrains the response of current genotypes. Improved understanding of plant N dynamics and ..