Functional responses of plants to elevated atmospheric CO 2 – do photosynthetic and productivity data from FACE experiments support early predictions?

Summary Results from 16 free‐air CO 2 enrichment (FACE) sites representing four different global vegetation types indicate that only some early predictions of the effects of increasing CO 2 concentration (elevated [CO 2 ]) on plant and ecosystem processes are well supported. Predictions for leaf CO 2 assimilation (A net ) generally fit our understanding of limitations to photosynthesis, and the FACE experiments indicate concurrent enhancement of photosynthesis and of partial downregulation. In addition, most herbaceous species had reduced leaf nitrogen (N)‐content under elevated [CO 2 ] and thus only a modest enhancement of A net , whereas most woody species had little change in leaf N with elevated [CO 2 ]…

• NS
  National Science Foundation
• UD
  U.S. Department of Energy