Relationships between needle nitrogen concentration and photosynthetic responses of Douglas-fir seedlings to elevated CO2 and temperature
Article first published online: 11 MAR 2004
Volume 162, Issue 2, pages 355–364, May 2004
How to Cite
Lewis, J. D., Lucash, M., Olszyk, D. M. and Tingey, D. T. (2004), Relationships between needle nitrogen concentration and photosynthetic responses of Douglas-fir seedlings to elevated CO2 and temperature. New Phytologist, 162: 355–364. doi: 10.1111/j.1469-8137.2004.01036.x
- Issue published online: 11 MAR 2004
- Article first published online: 11 MAR 2004
- Received: 1 November 2003 Accepted: 6 January 2004; doi: 10.1111/j.1469-8137.2004.01036.x
- carbon dioxide;
- climate change;
- Pseudotsuga menziesii (Douglas-fir);
- seasonal variation;
- • Here we examined correlations between needle nitrogen concentration ([N]) and photosynthetic responses of Douglas-fir (Pseudotsuga menziesii) seedlings to growth in elevated temperatures and atmospheric carbon dioxide concentrations ([CO2]).
- • Seedlings were grown in sunlit, climate-controlled chambers at ambient or ambient +3.5°C and ambient or ambient +180 µmol mol−1 CO2 in a full factorial design. Photosynthetic parameters and needle [N] were measured six times over a 21-month period.
- • Needle [N] varied seasonally, and accounted for 30–50% of the variation in photosynthetic parameters. Across measurement periods, elevated temperature increased needle [N] by 26% and light-saturated net photosynthetic rates by 17%. Elevated [CO2] decreased needle [N] by 12%, and reduced net photosynthetic rates measured at a common [CO2], maximum carboxylation activity (Vc,max) and electron transport capacity (Jmax), indicating photosynthetic acclimatization. Even so, elevated [CO2] enhanced net photosynthesis, and this effect increased with needle [N].
- • These results suggest that needle [N] may regulate photosynthetic responses of Douglas-fir to climate change. Further, needle [N] may be altered by climate change. However, effects of elevated [CO2] on photosynthesis may be similar across growth temperatures.