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Relationships between needle nitrogen concentration and photosynthetic responses of Douglas‐fir seedlings to elevated CO 2 and temperature
Author(s) -
Lewis J. D.,
Lucash M.,
Olszyk D. M.,
Tingey D. T.
Publication year - 2004
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2004.01036.x
Subject(s) - photosynthesis , carbon dioxide , acclimatization , carboxylation , nitrogen , photosynthetic capacity , zoology , botany , chemistry , horticulture , biology , biochemistry , organic chemistry , catalysis
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 ([CO 2 ]). • Seedlings were grown in sunlit, climate‐controlled chambers at ambient or ambient +3.5°C and ambient or ambient +180 µmol mol −1 CO 2 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 [CO 2 ] decreased needle [N] by 12%, and reduced net photosynthetic rates measured at a common [CO 2 ], maximum carboxylation activity ( V c,max ) and electron transport capacity ( J max ), indicating photosynthetic acclimatization. Even so, elevated [CO 2 ] 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 [CO 2 ] on photosynthesis may be similar across growth temperatures.