Skip to main content
Journal cover image

Sensitivity of mean canopy stomatal conductance to vapor pressure deficit in a flooded Taxodium distichum L. forest: hydraulic and non-hydraulic effects.

Publication ,  Journal Article
Oren, R; Sperry, JS; Ewers, BE; Pataki, DE; Phillips, N; Megonigal, JP
Published in: Oecologia
January 2001

We measured the xylem sap flux in 64-year-old Taxodium distichum (L.) Richard trees growing in a flooded forest using Granier-type sensors to estimate mean canopy stomatal conductance of the stand (G S). Temporal variations in G S were investigated in relation to variation in vapor pressure deficit (D), photosynthetic photon flux density (Q o), and the transpiration rate per unit of leaf area (E L), the latter variable serving as a proxy for plant water potential. We found that G S was only weakly related to Q o below 500 µmol m-2 s-1 (r 2=0.29), but unrelated to Q o above this value. Above Q o=500 µmol m-2 s-1 and D=0.6 kPa, G S decreased linearly with increasing E L with a poor fit (r 2=0.31), and linearly with lnD with a much better fit (r 2=0.81). The decrease of G S with lnD was at a rate predicted based on a simple hydraulic model in which stomata regulate the minimum leaf water potential. Based on the hydraulic model, stomatal sensitivity to D is proportional to stomatal conductance at low D. A hurricane caused an ~41% reduction in leaf area. This resulted in a 28% increase in G S at D=1 kPa (G Sref), indicating only partial compensation. As predicted, the increase in G Sref after the hurricane was accompanied by a similar increase in stomatal sensitivity to D (29%). At night, G Sref was ~20% of the daytime value under non-limiting light (Q o>500 µmol m-2 s-1). However, stomatal sensitivity to D decreased only to ~46% (both reductions referenced to pre-hurricane daytime values), thus having more than twice the sensitivity expected based on hydraulic considerations alone. Therefore, non-hydraulic processes must cause heightened nighttime stomatal sensitivity to D.

Duke Scholars

Published In

Oecologia

DOI

EISSN

1432-1939

ISSN

0029-8549

Publication Date

January 2001

Volume

126

Issue

1

Start / End Page

21 / 29

Related Subject Headings

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

Citation

APA
Chicago
ICMJE
MLA
NLM
Oren, R., Sperry, J. S., Ewers, B. E., Pataki, D. E., Phillips, N., & Megonigal, J. P. (2001). Sensitivity of mean canopy stomatal conductance to vapor pressure deficit in a flooded Taxodium distichum L. forest: hydraulic and non-hydraulic effects. Oecologia, 126(1), 21–29. https://doi.org/10.1007/s004420000497
Oren, R., J. S. Sperry, B. E. Ewers, D. E. Pataki, N. Phillips, and J. P. Megonigal. “Sensitivity of mean canopy stomatal conductance to vapor pressure deficit in a flooded Taxodium distichum L. forest: hydraulic and non-hydraulic effects.Oecologia 126, no. 1 (January 2001): 21–29. https://doi.org/10.1007/s004420000497.
Oren, R., et al. “Sensitivity of mean canopy stomatal conductance to vapor pressure deficit in a flooded Taxodium distichum L. forest: hydraulic and non-hydraulic effects.Oecologia, vol. 126, no. 1, Jan. 2001, pp. 21–29. Epmc, doi:10.1007/s004420000497.
Oren R, Sperry JS, Ewers BE, Pataki DE, Phillips N, Megonigal JP. Sensitivity of mean canopy stomatal conductance to vapor pressure deficit in a flooded Taxodium distichum L. forest: hydraulic and non-hydraulic effects. Oecologia. 2001 Jan;126(1):21–29.
Journal cover image

Published In

Oecologia

DOI

EISSN

1432-1939

ISSN

0029-8549

Publication Date

January 2001

Volume

126

Issue

1

Start / End Page

21 / 29

Related Subject Headings

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