Mycorrhizal association as a primary control of the CO₂ fertilization effect

• Published in: Science (American Association for the Advancement of Science) Vol. 353; no. 6294; pp. 72 - 74
• Main Authors: Terrer, César, Vicca, Sara, Hungate, Bruce A., Phillips, Richard P., Prentice, I. Colin
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 01.07.2016; The American Association for the Advancement of Science
• Subjects: Atmospherics; Availability; Biomass; Carbon Cycle; Carbon dioxide; Carbon Dioxide - metabolism; Climate; Climate Change; Fertilization; Fungi; Mycorrhizae - physiology; Nitrogen; Nitrogen - metabolism; Plant growth; Plants (organisms); Soil microorganisms
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.aaf4610

Plants buffer increasing atmospheric carbon dioxide (CO₂) concentrations through enhanced growth, but the question whether nitrogen availability constrains the magnitude of this ecosystem service remains unresolved. Synthesizing experiments from around the world, we show that CO₂ fertilization is best explained by a simple interaction between nitrogen availability and mycorrhizal association. Plant species that associate with ectomycorrhizal fungi show a strong biomass increase (30 ± 3%, P < 0.001) in response to elevated CO₂ regardless of nitrogen availability, whereas low nitrogen availability limits CO₂ fertilization (O ± 5%, P = 0.946) in plants that associate with arbuscular mycorrhizal fungi. The incorporation of mycorrhizae in global carbon cycle models is feasible, and crucial if we are to accurately project ecosystem responses and feedbacks to climate change.