Effect of elevated CO2 concentration and vapour pressure deficit on isoprene emission from leaves of Populus deltoides during drought

Emiliano Pegoraro, Ana Rey, Edward G. Bobich, Greg Barron-Gafford, Katherine Ann Grieve, Yadvinder Malhi, Ramesh Murthy

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57 Scopus citations


To further our understanding of the influence of global climate change on isoprene production we studied the effect of elevated [CO2] and vapour pressure deficit (VPD) on isoprene emission rates from leaves of Populus deltoides Bartr. during drought stress. Trees, grown inside three large bays with atmospheres containing 430, 800, or 1200 μmol mol-1 CO 2 at the Biosphere 2 facility, were subjected to a period of drought during which VPD was manipulated, switching between low VPD (approximately 1 kPa) and high VPD (approximately 3 kPa) for several days. When trees were not water-stressed, elevated [CO2] inhibited isoprene emission and stimulated photosynthesis. Isoprene emission was less responsive to drought than photosynthesis. As water-stress increased, the inhibition of isoprene emission disappeared, probably as a result of stomatal closure and the resulting decreases in intercellular [CO2] (Ci). This assumption was supported by increased isoprene emission under high VPD. Drought and high VPD dramatically increased the proportion of assimilated carbon lost as isoprene. When measured at the same [CO2], leaves from trees grown at ambient [CO2] always had higher isoprene emission rates than the leaves of trees grown at elevated [CO2], demonstrating that CO2 inhibition is a long-term effect.

Original languageEnglish (US)
Article numberFP04142
Pages (from-to)1137-1147
Number of pages11
JournalFunctional Plant Biology
Issue number12
StatePublished - 2004


  • Biosphere 2 Laboratory
  • Carbon loss
  • Cottonwood
  • Elevated CO
  • Intercellular CO concentration
  • Isoprene production
  • Photosynthesis
  • Populus deltoides
  • Stomatal conductance
  • Water-stress

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Plant Science


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