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Leaf and canopy responses to elevated CO2 in a pine forest under free-air CO2 enrichment.

Publication ,  Journal Article
Ellsworth, DS; Oren, R; Huang, C; Phillips, N; Hendrey, GR
Published in: Oecologia
October 1995

Physiological responses to elevated CO2 at the leaf and canopy-level were studied in an intact pine (Pinus taeda) forest ecosystem exposed to elevated CO2 using a free-air CO2 enrichment (FACE) technique. Normalized canopy water-use of trees exposed to elevated CO2 over an 8-day exposure period was similar to that of trees exposed to current ambient CO2 under sunny conditions. During a portion of the exposure period when sky conditions were cloudy, CO2-exposed trees showed minor (≤7%) but significant reductions in relative sap flux density compared to trees under ambient CO2 conditions. Short-term (minutes) direct stomatal responses to elevated CO2 were also relatively weak (≈5% reduction in stomatal aperture in response to high CO2 concentrations). We observed no evidence of adjustment in stomatal conductance in foliage grown under elevated CO2 for nearly 80 days compared to foliage grown under current ambient CO2, so intrinsic leaf water-use efficiency at elevated CO2 was enhanced primarily by direct responses of photosynthesis to CO2. We did not detect statistical differences in parameters from photosynthetic responses to intercellular CO2 (A net-C i curves) for Pinus taeda foliage grown under elevated CO2 (550 μmol mol-1) for 50-80 days compared to those for foliage grown under current ambient CO2 from similar-sized reference trees nearby. In both cases, leaf net photosynthetic rate at 550 μmol mol-1 CO2 was enhanced by approximately 65% compared to the rate at ambient CO2 (350 μmol mol-1). A similar level of enhancement under elevated CO2 was observed for daily photosynthesis under field conditions on a sunny day. While enhancement of photosynthesis by elevated CO2 during the study period appears to be primarily attributable to direct photosynthetic responses to CO2 in the pine forest, longer-term CO2 responses and feedbacks remain to be evaluated.

Duke Scholars

Published In

Oecologia

DOI

EISSN

1432-1939

ISSN

0029-8549

Publication Date

October 1995

Volume

104

Issue

2

Start / End Page

139 / 146

Related Subject Headings

  • Ecology
  • 3109 Zoology
  • 3104 Evolutionary biology
  • 3103 Ecology
  • 0602 Ecology
 

Citation

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Ellsworth, D. S., Oren, R., Huang, C., Phillips, N., & Hendrey, G. R. (1995). Leaf and canopy responses to elevated CO2 in a pine forest under free-air CO2 enrichment. Oecologia, 104(2), 139–146. https://doi.org/10.1007/bf00328578
Ellsworth, David S., Ram Oren, Ce Huang, Nathan Phillips, and George R. Hendrey. “Leaf and canopy responses to elevated CO2 in a pine forest under free-air CO2 enrichment.Oecologia 104, no. 2 (October 1995): 139–46. https://doi.org/10.1007/bf00328578.
Ellsworth DS, Oren R, Huang C, Phillips N, Hendrey GR. Leaf and canopy responses to elevated CO2 in a pine forest under free-air CO2 enrichment. Oecologia. 1995 Oct;104(2):139–46.
Ellsworth, David S., et al. “Leaf and canopy responses to elevated CO2 in a pine forest under free-air CO2 enrichment.Oecologia, vol. 104, no. 2, Oct. 1995, pp. 139–46. Epmc, doi:10.1007/bf00328578.
Ellsworth DS, Oren R, Huang C, Phillips N, Hendrey GR. Leaf and canopy responses to elevated CO2 in a pine forest under free-air CO2 enrichment. Oecologia. 1995 Oct;104(2):139–146.
Journal cover image

Published In

Oecologia

DOI

EISSN

1432-1939

ISSN

0029-8549

Publication Date

October 1995

Volume

104

Issue

2

Start / End Page

139 / 146

Related Subject Headings

  • Ecology
  • 3109 Zoology
  • 3104 Evolutionary biology
  • 3103 Ecology
  • 0602 Ecology