Fig. 1.

Direct and indirect effects of rising [CO₂] on plant development and phenology, plant physiology and water dynamics, and plant interactions with other organisms can have cascading effects on ecological and evolutionary processes across spatial and temporal scales (a). Here we highlight examples of key questions in CO₂ research that will require an integrative approach that bridges gaps between molecular biology, plant physiology, ecological and evolutionary biology, and ecosystem science (b). This is by no means an exhaustive list, and not all questions are specifically discussed in the main text. Images show (a1) a developing Arabidopsis flower bud, (a2) stoma (upper image, Juniperus) and xylem (lower image, Picea) structures, and (a3) arbuscular mycorrhizal fungi colonizing herbaceous roots. Images were provided courtesy of R. Atkinson, K. M. Becklin, V. Bui, and S. M. Walker. FLT, flowering time; PSF, plant–soil feedback.