Is xylem of angiosperm leaves less resistant to embolism than branches? Insights from microCT, hydraulics, and anatomy

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Matthias Klepsch - , Ulm University (Author)
  • Ya Zhang - , Ulm University (Author)
  • Martyna M. Kotowska - , Macquarie University, University of Göttingen (Author)
  • Laurent J. Lamarque - , Université de Bordeaux, Bordeaux Sciences Agro (Author)
  • Markus Nolf - , Western Sydney University (Author)
  • Bernhard Schuldt - , University of Göttingen (Author)
  • José M. Torres-Ruiz - , Université de Bordeaux, Université Clermont Auvergne (Author)
  • De Wen Qin - , Guangxi University (Author)
  • Brendan Choat - , Western Sydney University (Author)
  • Sylvain Delzon - , Université de Bordeaux (Author)
  • Christine Scoffoni - , California State University Los Angeles (Author)
  • Kun Fang Cao - , Guangxi University (Author)
  • Steven Jansen - , Ulm University (Author)

Abstract

According to the hydraulic vulnerability segmentation hypothesis, leaves are more vulnerable to decline of hydraulic conductivity than branches, but whether stem xylem is more embolism resistant than leaves remains unclear. Drought-induced embolism resistance of leaf xylem was investigated based on X-ray microcomputed tomography (microCT) for Betula pendula, Laurus nobilis, and Liriodendron tulipifera, excluding outside-xylem, and compared with hydraulic vulnerability curves for branch xylem. Moreover, bordered pit characters related to embolism resistance were investigated for both organs. Theoretical P50 values (i.e. the xylem pressure corresponding to 50% loss of hydraulic conductance) of leaves were generally within the same range as hydraulic P50 values of branches. P50 values of leaves were similar to branches for L. tulipifera (−2.01 versus −2.10 MPa, respectively), more negative for B. pendula (−2.87 versus −1.80 MPa), and less negative for L. nobilis (−6.4 versus −9.2 MPa). Despite more narrow conduits in leaves than branches, mean interconduit pit membrane thickness was similar in both organs, but significantly higher in leaves of B. pendula than in branches. This case study indicates that xylem shows a largely similar embolism resistance across leaves and branches, although differences both within and across organs may occur, suggesting interspecific variation with regard to the hydraulic vulnerability segmentation hypothesis.

Details

Original languageEnglish
Pages (from-to)5611-5623
Number of pages13
JournalJournal of experimental botany
Volume69
Issue number22
Publication statusPublished - 2018
Peer-reviewedYes
Externally publishedYes

External IDs

PubMed 30184113

Keywords

ASJC Scopus subject areas

Keywords

  • Bordered pit, Branch, Embolism, Hydraulic segmentation, Leaf, MicroCT, Pit membrane, Xylem