Effects of drought and changes in vapour pressure deficit on water relations of Populus deltoides growing in ambient and elevated CO2

Edward G. Bobich, Greg A Barron-Gafford, Katherine G. Rascher, Ramesh Murthy

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

The means by which growth CO2 concentration ([CO2]) affects anatomy and water relations responses to drought and vapour pressure deficit (VPD) were studied for yearly coppiced, 4-year-old Populus deltoides clones that were grown in either 400 μmol mol-1 (ambient) or 800 μmol mol-1 (elevated) CO2 for 3 years. It was hypothesized that, during drought, trees growing in elevated [CO2] would have a lower volume flux density of water (JV), stomatal conductance (gs) and transpiration per leaf area (E), as well as a lower stomatal density and a greater stomatal response to drought and changes in VPD than would trees in ambient [CO2]. Trees in elevated [CO2] actually had higher JV values throughout the study, but did not differ from trees in ambient [CO2] with respect to gs or E under saturating light or E scaled from JV (Escaled), all of which indicates that the higher JV in elevated [CO 2] resulted from those trees having greater leaf area and not from differences in gs. Furthermore, although plants in elevated [CO2] had greater absolute leaf loss during the drought, the percentage of leaf area lost was similar to that of trees in ambient [CO2]. gs and E under saturating light were affected by changes in VPD after the first 9 days of the experiment, which coincided with a large decrease in water potential at a soil depth of 0.1 m. Trees in elevated [CO2] had a greater stomatal density and a lower wood density than trees in ambient [CO2], both traits that may make the trees more susceptible to xylem cavitation in severe drought. Drought and VPD effects for the P. deltoides clone were not ameliorated by long-term growth in elevated [CO2] compared with ambient [CO 2], and plants in elevated [CO2] possessed anatomical traits that may result in greater stress associated with long-term drought.

Original languageEnglish (US)
Pages (from-to)866-875
Number of pages10
JournalTree Physiology
Volume30
Issue number7
DOIs
StatePublished - Jul 2010

Fingerprint

Populus
Vapor Pressure
Populus deltoides
Droughts
vapor pressure
drought
Water
water
leaf area
Carbon Monoxide
Clone Cells
clones
Light
Xylem
wood density
Growth
water potential
soil depth
xylem
stomatal conductance

Keywords

  • cottonwood
  • stomatal conductance
  • stomatal density
  • transpiration
  • volume flux density
  • wood density

ASJC Scopus subject areas

  • Plant Science
  • Physiology
  • Medicine(all)

Cite this

Effects of drought and changes in vapour pressure deficit on water relations of Populus deltoides growing in ambient and elevated CO2. / Bobich, Edward G.; Barron-Gafford, Greg A; Rascher, Katherine G.; Murthy, Ramesh.

In: Tree Physiology, Vol. 30, No. 7, 07.2010, p. 866-875.

Research output: Contribution to journalArticle

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