Phosphorus supply drives nonlinear responses of cottonwood (Populus deltoides) to increases in CO2 concentration from glacial to future concentrations.
*Despite the importance of nutrient availability in determining plant responses to climate change, few studies have addressed the interactive effects of phosphorus (P) supply and rising atmospheric CO(2) concentration ([CO(2)]) from glacial to modern and future concentrations on tree seedling growth. *The objective of our study was to examine interactive effects across a range of P supply (six concentrations from 0.004 to 0.5 mM) and [CO(2)] (200 (glacial), 350 (modern) and 700 (future) ppm) on growth, dry mass allocation, and light-saturated photosynthesis (A(sat)) in Populus deltoides (cottonwood) seedlings grown in well-watered conditions. *Increasing [CO(2)] from glacial to modern concentrations increased growth by 25% across P treatments, reflecting reduced [CO(2)] limitations to photosynthesis and increased A(sat). Conversely, the growth response to future [CO(2)] was very sensitive to P supply. Future [CO(2)] increased growth by 80% in the highest P supply but only by 7% in the lowest P supply, reflecting P limitations to A(sat), leaf area and leaf area ratio (LAR), compared with modern [CO(2)]. *Our results suggest that future [CO(2)] will minimally increase cottonwood growth in low-P soils, but in high-P soils may stimulate production to a greater extent than predicted based on responses to past increases in [CO(2)]. Our results indicate that the capacity for [CO(2)] stimulation of cottonwood growth does not decline as [CO(2)] rises from glacial to future concentrations.
Lewis
James D
JD
Centre for Plants and the Environment, University of Western Sydney, Richmond, NSW 2753, Australia.|Louis Calder Center, Biological Field Station, and Department of Biological Sciences, Fordham University, P.O. Box 887, Armonk, NY 10504, USA.
Ward
Joy K
JK
Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66049, USA.
Tissue
David T
DT
Centre for Plants and the Environment, University of Western Sydney, Richmond, NSW 2753, Australia.|Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA.
D018533:Biomass; D002245:Carbon Dioxide / Q000378:metabolism / Q000494:pharmacology*; D008027:Light; D017711:Nonlinear Dynamics; D010758:Phosphorus / Q000378:metabolism*; D018515:Plant Leaves / Q000033:anatomy & histology / Q000378:metabolism / Q000528:radiation effects; D018517:Plant Roots / Q000033:anatomy & histology / Q000378:metabolism / Q000528:radiation effects; D018547:Plant Stems / Q000033:anatomy & histology / Q000378:metabolism / Q000528:radiation effects; D032107:Populus / Q000187:drug effects* / Q000254:growth & development / Q000528:radiation effects; D036226:Seedlings / Q000254:growth & development / Q000528:radiation effects
D002245:Carbon Dioxide; D010758:Phosphorus