Editor: Navin Ramankutty
Altered root traits due to elevated CO2: a meta-analysis
Version of Record online: 17 APR 2013
© 2013 John Wiley & Sons Ltd
Global Ecology and Biogeography
Volume 22, Issue 10, pages 1095–1105, October 2013
How to Cite
Nie, M., Lu, M., Bell, J., Raut, S. and Pendall, E. (2013), Altered root traits due to elevated CO2: a meta-analysis. Global Ecology and Biogeography, 22: 1095–1105. doi: 10.1111/geb.12062
- Issue online: 4 SEP 2013
- Version of Record online: 17 APR 2013
- US Department of Energy's Office of Science (BER)
- National Science Foundation. Grant Number: 1021559
- China National Natural Science Foundation for Young Scholars. Grant Number: 31100352
- C sequestration;
- free-air CO2 enrichment;
- open top chamber;
- plant root
Plant root traits regulate belowground C inputs, soil nutrient and water uptake, and play critical roles in determining sustainable plant production and consequences for ecosystem C storage. However, the effects of elevated CO2 on root morphology and function have not been well quantified. We reveal general patterns of root trait responses to elevated CO2 from field manipulative experiments.
North America, Europe, Oceania, Asia.
The meta-analysis approach was used to examine the effects of CO2 elevation on 17 variables associated with root morphology, biomass size and distribution, C and N concentrations and pools, turnover and fungal colonization from 110 published studies.
Elevated CO2 increased root length (+26.0%) and diameter (+8.4%). Elevated CO2 also stimulated total root (+28.8%), fine root (+27.7%) and coarse root biomass (+25.3%), demonstrating strong responses of root morphology and biomass. Elevated CO2 increased the root:shoot ratio (+8.5%) and decreased the proportion of roots in the topsoil (–8.4%), suggesting that plants expand rooting systems. In addition, elevated CO2 decreased N concentration (–7.1%), but did not affect C concentration, and thus increased the C:N ratio (+7.8%). Root C (+29.3%) increased disproportionately relative to root N pools (+9.4%) under elevated CO2. Functional traits were also strongly affected by elevated CO2, which increased respiration (+58.9%), rhizodeposition (+37.9%) and fungal colonization (+3.3%).
These results suggest that elevated CO2 promoted root morphological development, root system expansion and C input to soils, implying that the sensitive responses of root morphology and function to elevated CO2 would increase long-term belowground C sequestration.