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Relationships between needle nitrogen concentration and photosynthetic responses of Douglas-fir seedlings to elevated CO2 and temperature
Article first published online: 11 MAR 2004
DOI: 10.1111/j.1469-8137.2004.01036.x
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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
Publication History
- 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
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Keywords:
- acclimatization;
- carbon dioxide;
- climate change;
- nitrogen;
- photosynthesis;
- Pseudotsuga menziesii (Douglas-fir);
- seasonal variation;
- temperature
Summary
- • 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.

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