Down-regulation of tissue N:P ratios in terrestrial plants by elevated CO2

• Published in: Ecology (Durham) 2015-12, Vol.96 (12), p.3354-3362
• Main Authors: Deng, Qi, Hui, Dafeng, Luo, Yiqi, Elser, James, Wang, Ying-Ping, Loladze, Irakli, Zhang, Quanfa, Dennis, Sam
• Format: Article
• Language: English
• Subjects: Carbon Dioxide - chemistry; Carbon Dioxide - pharmacology; Climate Change; Down-Regulation - physiology; Ecosystems; element stoichiometry; elevated CO; elevated CO2; Grassland soils; growth rate hypothesis; meta-analysis; Nitrogen; Nitrogen - metabolism; nutrient dynamics; Phosphorus - chemistry; Phosphorus - metabolism; Plant ecology; Plant growth; Plants; Plants - drug effects; Plants - metabolism; progressive nitrogen limitation; Soil - chemistry; Soil ecology; Soil mechanics; Stoichiometry; Terrestrial ecosystems
• ISSN: 0012-9658; 1939-9170
• DOI: 10.1890/15-0217.1

Increasing atmospheric CO 2 concentrations generally alter element stoichiometry in plants. However, a comprehensive evaluation of the elevated CO 2 impact on plant nitrogen : phosphorus (N:P) ratios and the underlying mechanism has not been conducted. We synthesized the results from 112 previously published studies using meta-analysis to evaluate the effects of elevated CO 2 on the N:P ratio of terrestrial plants and to explore the underlying mechanism based on plant growth and soil P dynamics. Our results show that terrestrial plants grown under elevated CO 2 had lower N:P ratios in both above- and belowground biomass across different ecosystem types. The response ratio for plant N:P was negatively correlated with the response ratio for plant growth in croplands and grasslands, and showed a stronger relationship for P than for N. In addition, the CO 2 -induced down-regulation of plant N:P was accompanied by 19.3% and 4.2% increases in soil phosphatase activity and labile P, respectively, and a 10.1% decrease in total soil P. Our results show that down-regulation of plant N:P under elevated CO 2 corresponds with accelerated soil P cycling. These findings should be useful for better understanding of terrestrial plant stoichiometry in response to elevated CO 2 and of the underlying mechanisms affecting nutrient dynamics under climate change.