Title: Relationship between stem CO2 efflux, stem sap velocity and xylem CO2 concentration in young loblolly pine trees
Author: Maier, Chris A.; Clinton, Barton D.;
Source: Plant, Cell and Environment Vol. 26: 1471-1483
Publication Series: Miscellaneous Publication
Description: 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.
Keywords: Chambers, CO2, microelectrode, granier sensors, Pinus taeda, sap flow, stem respiration
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
- You may send email to email@example.com to request a hard copy of this publication. (Please specify exactly
which publication you are requesting and your mailing address.)
XML: View XML
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
Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility