Interactions between increasing CO2 concentration and temperature on plant growth

The global environment is changing with increasing temperature and atmospheric carbon dioxide concentration, CO₂]. Because these two factors are concomitant, and the global CO₂] rise will affect all biomes across the full global range of temperatures, it is essential to review the theory and observations on effects of temperature and CO₂] interactions on plant carbon balance, growth, development, biomass accumulation and yield. Although there are sound theoretical reasons for expecting a larger stimulation of net CO₂ assimilation rates by increased CO₂] at higher temperatures, this does not necessarily mean that the pattern of biomass and yield responses to increasing CO₂] and temperature is determined by this response. This paper reviews the interactions between the effects of CO₂] and temperature on plants. There is little unequivocal evidence for large differences in response to CO₂] at different temperatures, as studies are confounded by the different responses of species adapted and acclimated to different temperatures, and the interspecific differences in growth form and development pattern. We conclude by stressing the importance of initiation and expansion of meristems and organs and the balance between assimilate supply and sink activity in determining the growth response to increasing CO₂] and temperature.