Relationship between stem CO2 efflux, stem sap velocity and xylem CO2 concentration in young loblolly pine trees

Download
(PDF; 644 KB)
Cite
Feedback
  • Authors: Maier, Chris A.; Clinton, Barton D.
  • Publication Year: 2006
  • Publication Series: Miscellaneous Publication
  • Source: Plant, Cell and Environment Vol. 26: 1471-1483

Abstract

We measured diel patterns of stem surface CO2 efflux (Es, mol m-2 s-1), sap velocity (Vs, mn s-1) and xylem CO2 concentration ([CO2]) (Xs, %) in 8-year-old loblolly pine trees during the spring to determine how v, and X, influence Es. All trees showed a strong diel hysteresis between Es and stem temperature, where at a given temperature, Es, was lower during the day than at night. Diel variation in temperature-independent Es were correlated with Vs (R2 = 0.54), such that at maximum vs, Es was reduced between 18 and 40%. However, this correlation may not represent a cause-and-effect relationship. In a subset of trees, vs was artificially reduced by progressively removing the tree canopy. Reducing vs to near zero had no effect on Es and did not change the diel hysteretic response to temperature. Diel xs tended to decrease the Vs and increase with Es, however, in defoliated trees, large increases in Xs, when vs = 0, had no effect on Es. We conclude that at this time of the year, Es, is driven primarily by respiration of cambium and phloem tissues and that sap flow and xylem transport of CO2 had no direct influence on Es.

  • Citation: Maier, Chris A.; Clinton, Barton D. 2006. Relationship between stem CO2 efflux, stem sap velocity and xylem CO2 concentration in young loblolly pine trees. Plant, Cell and Environment Vol. 26: 1471-1483
  • Keywords: Chambers, CO2, microelectrode, granier sensors, Pinus taeda, sap flow, stem respiration
  • Posted Date: June 27, 2006
  • Modified Date: August 22, 2006

    • Print Publications Are No Longer Available

    In an ongoing effort to be fiscally responsible, the Southern Research Station (SRS) will no longer produce and distribute hard copies of our publications. Many SRS publications are available at cost via the Government Printing Office (GPO). Electronic versions of publications may be downloaded, printed, and distributed.

    Publication Notes

    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
    • Our online publications are scanned and captured using Adobe Acrobat. During the capture process some typographical errors may occur. Please contact the SRS webmaster if you notice any errors which make this publication unusable.
    • To view this article, download the latest version of Adobe Acrobat Reader.