Photosynthesis and stomatal conductance responses of poplars to free-air CO2 enrichment (PopFACE) during the first growth cycle and immediately following coppice

C. J. Bernacchi, C. Calfapietra, P. A. Davey, V. E. Wittig, G. E. Scarascia-Mugnozza, C. A. Raines, S. P. Long

Research output: Contribution to journalArticle

Abstract

• Using the Poplar Free Air CO2 Enrichement (PopFACE) facility we investigated the effects of elevated [CO2] on the diurnal and growth cycle responses of photosynthesis and conductance in three poplar species. • In situ diurnal measurements of photosynthesis were made on Populus alba, P. nigra and P. x euramericana and, in parallel, in vivo maximum capacity for carboxylation (Vc,max) and maximum rates of electron transport (Jmax) were determined by gas exchange measurement. • Light saturated (Asat) and daily integrated (A′) photosynthesis increased at elevated [CO2] in all species. Elevated [CO2] decreased Vc,max and Jmax for P. nigra and Jmax for P. x euramericana but had no effect on stomatal conductance in any of the species throughout the first growth cycle. During post-coppice re-growth, elevated [CO2] did not increase A sat in P. nigra and P. x euramericana due to large decreases in Vc,max and Jmax. • A 50% increase in [CO 2] under these open-air field conditions resulted in a large and sustained increase in Asat. Although there were some differences between the species, these had little effect on photosynthetic rates at the growth [CO2]. Nevertheless the results show that even fast growing trees grown without rooting volume restriction in the open may still show some down-regulation of photosynthetic potential at elevated [CO2].

Original languageEnglish (US)
Pages (from-to)609-621
Number of pages13
JournalNew Phytologist
Volume159
Issue number3
DOIs
StatePublished - Sep 1 2003

Keywords

  • Atmospheric change
  • Climate change
  • Elevated CO
  • Free Air CO Enrichment (FACE)
  • Photosynthetic electron transport
  • Populus spp.
  • Rubisco

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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