Cutting xylem under tension or supersaturated with gas can generate PLC and the appearance of rapid recovery from embolism
TLDR
The results suggest that sampling methods can generate PLC patterns indicative of repair under tension by inducing a degree of embolism that is itself a function of xylem tensions or supersaturation of dissolved gases (air injection) at the moment of sample excision.Abstract:
We investigated the common assumption that severing stems and petioles under water preserves the hydraulic continuity in the xylem conduits opened by the cut when the xylem is under tension. In red maple and white ash, higher percent loss of conductivity (PLC) in the afternoon occurred when the measurement segment was excised under water at native xylem tensions, but not when xylem tensions were relaxed prior to sample excision. Bench drying vulnerability curves in which measurement samples were excised at native versus relaxed tensions showed a dramatic effect of cutting under tension in red maple, a moderate effect in sugar maple, and no effect in paper birch. We also found that air injection of cut branches (red and sugar maple) at pressures of 0.1 and 1.0 MPa resulted in PLC greater than predicted from vulnerability curves for samples cut 2 min after depressurization, with PLC returning to expected levels for samples cut after 75 min. These results suggest that sampling methods can generate PLC patterns indicative of repair under tension by inducing a degree of embolism that is itself a function of xylem tensions or supersaturation of dissolved gases (air injection) at the moment of sample excision. Implications for assessing vulnerability to cavitation and levels of embolism under field conditions are discussed.read more
Citations
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Journal ArticleDOI
A multi-species synthesis of physiological mechanisms in drought-induced tree mortality
Henry D. Adams,Melanie J. B. Zeppel,Melanie J. B. Zeppel,William R. L. Anderegg,Henrik Hartmann,Simon M. Landhäusser,David T. Tissue,Travis E. Huxman,Patrick J. Hudson,Trenton E. Franz,Craig D. Allen,Leander D. L. Anderegg,Greg A. Barron-Gafford,David J. Beerling,David D. Breshears,Timothy J. Brodribb,Harald Bugmann,Richard Cobb,Adam D. Collins,L. Turin Dickman,Honglang Duan,Brent E. Ewers,Lucía Galiano,David A. Galvez,Núria Garcia-Forner,Monica L. Gaylord,Monica L. Gaylord,Matthew J. Germino,Arthur Gessler,Uwe G. Hacke,Rodrigo Hakamada,Andy Hector,Michael W. Jenkins,Jeffrey M. Kane,Thomas Kolb,Darin J. Law,James D. Lewis,Jean-Marc Limousin,David M. Love,Alison K. Macalady,Jordi Martínez-Vilalta,Maurizio Mencuccini,Patrick J. Mitchell,J. D. Muss,Michael O'Brien,Anthony P. O'Grady,Robert E. Pangle,Elizabeth A. Pinkard,Frida I. Piper,Jennifer A. Plaut,William T. Pockman,Joe Quirk,Keith Reinhardt,Francesco Ripullone,Michael G. Ryan,Michael G. Ryan,Anna Sala,Sanna Sevanto,John S. Sperry,Rodrigo Vargas,Michel Vennetier,Danielle A. Way,Danielle A. Way,Chonggang Xu,Enrico A. Yepez,Nate G. McDowell +65 more
TL;DR: It is shown that, across multiple tree species, loss of xylem conductivity above 60% is associated with mortality, while carbon starvation is not universal, indicating that evidence supporting carbon starvation was not universal.
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Drought survival of tropical tree seedlings enhanced by non-structural carbohydrate levels
Michael O'Brien,Sebastian Leuzinger,Christopher D. Philipson,John Tay,Andy Hector,Andy Hector +5 more
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Methods for measuring plant vulnerability to cavitation: a critical review
TL;DR: A panorama of the techniques used to generate a 'vulnerability curve' (VC) shows the variation of the percentage of cavitation as a function of xylem pressure potential, and it was found that the vast majority of curves obtained with the reference bench dehydration-PLC method are 'sigmoidal'.
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What plant hydraulics can tell us about responses to climate-change droughts.
John S. Sperry,David M. Love +1 more
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References
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Book
Xylem Structure and the Ascent of Sap
TL;DR: Xylem Dysfunction: When Cohesion Breaks Down, the Cohesion-Tension Theory of Sap Ascent and other Functional Adaptations.
Book
Water Relations of Plants and Soils
Paul J. Kramer,John S. Boyer +1 more
TL;DR: This book is a useful introduction for students, teachers, and investigators in both basic and applied plant science, including botanists, crop scientists, foresters, horticulturists, soil scientists, and even gardeners and farmers who desire a better understanding of how their plants grow.
Journal ArticleDOI
Global convergence in the vulnerability of forests to drought
Brendan Choat,Steven Jansen,Timothy J. Brodribb,Hervé Cochard,Hervé Cochard,Sylvain Delzon,Radika Bhaskar,Sandra Janet Bucci,Taylor S. Feild,Sean M. Gleason,Uwe G. Hacke,Anna L. Jacobsen,Frederic Lens,Hafiz Maherali,Jordi Martínez-Vilalta,Stefan Mayr,Maurizio Mencuccini,Patrick J. Mitchell,Andrea Nardini,Jarmila Pittermann,R. Brandon Pratt,John S. Sperry,Mark Westoby,Ian J. Wright,Amy E. Zanne,Amy E. Zanne +25 more
TL;DR: In this article, the authors draw together published and unpublished data on the vulnerability of the transport system to drought-induced embolism for a large number of woody species, with a view to examining the likely consequences of climate change for forest biomes.
Journal ArticleDOI
A method for measuring hydraulic conductivity and embolism in xylem
TL;DR: In this article, the authors measured the hydraulic conductivity of the xylem and found that certain perfusing solutions including dilute fixatives (e.g. 0.05% formaldehyde) and acids with pH below 3 prevent long-term decline in conductivity.
Journal ArticleDOI
Xylem Embolism in Ring-Porous, Diffuse-Porous, and Coniferous Trees of Northern Utah and Interior Alaska
TL;DR: Differences between sites in northern Utah and interior Alaska were explained by vulnerability to embolism caused by freeze-thaw cycles, whereas most conifers were entirely resistant, whereas dicot trees were vulner- able.
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Global convergence in the vulnerability of forests to drought
Brendan Choat,Steven Jansen,Timothy J. Brodribb,Hervé Cochard,Hervé Cochard,Sylvain Delzon,Radika Bhaskar,Sandra Janet Bucci,Taylor S. Feild,Sean M. Gleason,Uwe G. Hacke,Anna L. Jacobsen,Frederic Lens,Hafiz Maherali,Jordi Martínez-Vilalta,Stefan Mayr,Maurizio Mencuccini,Patrick J. Mitchell,Andrea Nardini,Jarmila Pittermann,R. Brandon Pratt,John S. Sperry,Mark Westoby,Ian J. Wright,Amy E. Zanne,Amy E. Zanne +25 more