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A meta‐analysis of leaf gas exchange and nitrogen in trees grown under elevated carbon dioxide
Author(s) -
CURTIS P. S.
Publication year - 1996
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.1996.tb00234.x
Subject(s) - carbon dioxide , respiration , stomatal conductance , nitrogen , specific leaf area , horticulture , photosynthesis , acclimatization , chemistry , zoology , botany , agronomy , biology , organic chemistry
The response of trees to rising atmospheric CO 2 concentration ([CO 2 ]) is of concern to forest ecologists and global carbon modellers and is the focus of an increasing body of research work. I review studies published up to May 1994, and several unpublished works, which reported at least one of the following: net CO 2 assimilation ( A ), stomatal conductance ( g s ), leaf dark respiration ( R d ) leaf nitrogen or specific leaf area (SLA) in woody plants grown at <400 μmol mol −1 CO 2 or at 600–800 μmol mol −1 CO 2 . The resulting data from 41 species were categorized according to growth conditions (unstressed versus stressed), length of CO 2 exposure, pot size and exposure facility [growth chamber (GC), greenhouse (GH), or open‐top chamber (OTC)] and interpreted using meta‐analytic methods. Overall, A showed a large and significant increase at elevated [CO 2 ] but length of CO 2 exposure and the exposure facility were important modifiers of this response. Plants exposed for < 50 d had a significantly greater response, and those from GCs had a significantly lower response than plants from longer exposures or from OTC studies. Negative acclimation of A was significant and general among stressed plants, but in unstressed plants was influenced by length of CO 2 exposure, the exposure facility and/or pot size. Growth at elevated [CO 2 ] resulted in moderate reductions in gs in unstressed plants, but there was no significant effect of CO 2 on gs in stressed plants. Leaf dark respiration (mass or area basis) was reduced strongly by growth at high [CO 2 ] > while leaf N was reduced only when expressed on a mass basis. This review is the first meta‐analysis of elevated CO 2 studies and provides statistical confirmation of several general responses of trees to elevated [CO 2 ]. It also highlights important areas of continued uncertainty in our understanding of these responses.