OOS 75
The Effects of Drought on the Formation, Resilience, and Recovery of Xylem Embolism in Plants: Linking Experimental Results and Synthesizing Observations

Thursday, August 13, 2015: 1:30 PM-5:00 PM
327, Baltimore Convention Center
James D. Lewis, Fordham University
Melanie J.B. Zeppel, Macquarie University; Henry D. Adams, Los Alamos National Laboratory; and Anna L. Jacobsen, California State University, Bakersfield
James D. Lewis, Fordham University
Emerging advances in ecological research have progressed our understanding of the complex process through which woody plants succumb to drought and temperature stress. Recent and ongoing experiments have begun to illuminate the interactions among water relations, carbon status and biotic agent damage with a goal of improving predictions of which species and regions are likely to experience woody plant death and dieback in future climates. Despite this progress, however, major uncertainties remain both in how trees succumb to drought and in understanding cross-species and cross-biome differences. This session seeks to capture the forefront of this exciting research area by integrating cutting-edge physiological research on single species and specific ecosystems with cross-system comparisons and syntheses. Drought induced embolism and the subsequent recovery is a new and rapidly expanding area of research. Although the mechanisms of refilling embolism under positive pressure, and via new growth over seasons, is well understood, the mechanisms involved in embolism refilling in different tissues, species and biomes remain unresolved. Other aspects of embolism refilling, such as the timeframes under which different types of embolism refilling can occur, are also hotly debated, with causative mechanisms needing further elucidation. Further, species differ in their resilience to high levels of embolism, and different species likely exhibit different embolism thresholds. This session provides a mix of novel research and syntheses on a highly debated and currently unresolved field of research. We have six confirmed speakers focusing on different ecosystems, so we can introduce a robust and diverse understanding of embolism recovery and mortality avoidance based upon water relations, life history traits, and microclimatic conditions across several plant functional types. Additionally, speakers working in regions including Europe, California chapparal, the tropics, southwestern U.S. coniferous forests and the southern hemisphere will provide insights into research across a broad range of ecosystems. We have confirmations from a mix of energetic ‘rising star’ early career scientists, and established professors providing overviews of recent embolism research.
1:30 PM
 What plant hydraulics can tell us about responses to climate-change droughts
John S. Sperry, University of Utah; David Love, University of Utah
1:50 PM
2:10 PM
 Embolism repair, refilling and recovery: A synthesis of structures, processes & trade-offs involved in refilling, a comparison of methodological strengths and weaknesses
Melanie J.B. Zeppel, Macquarie University; Tamir Klein, University of Basel; William R. L. Anderegg, Princeton University; Jasper Bloemen, University of Innsbruck; Patrick Hudson, University of New Mexico; Nadine Ruehr, Karlsruhe Institute of Technology; Thomas Powell, Harvard University; Georg Von Arx, Swiss Federal Institute WSL; Andrea Nardini, Università di Trieste
2:30 PM
 Living with cavitation: Sub-diurnal cycles of xylem cavitation and recovery in pine trees under seasonal drought
Tamir Klein, University of Basel; Shabtai Cohen, ARO Volcani Center; Eyal Rotenberg, Weizmann Institute of Science; Dan Yakir, Weizmann Institute of Science
2:50 PM
 A test of the hydraulic vulnerability segmentation hypothesis in angiosperm and conifer tree species
Daniel M. Johnson, University of Idaho; Rémi Wortemann, Duke University; Katherine A. McCulloh, The University of Wisconsin-Madison; Lionel Jordan-Meille, Bordeaux Sciences Agro; Eric Ward, Oak Ridge National Laboratory; Jeffrey M. Warren, Oak Ridge National Laboratory; Robert B. Jackson, Stanford University; Sari Palmroth, Duke University; Jean-Christophe Domec, Duke University / Bordeaux Sciences Agro
3:10 PM
3:20 PM
 Drought response syndromes, microclimates and vulnerability of a woodland community during severe drought
Blair C. McLaughlin, University of Idaho; Anna L. Jacobsen, California State University, Bakersfield; R. Brandon Pratt, California State University, Bakersfield; Todd E. Dawson, University of California Berkeley; David D. Ackerly, University of California; Andrew P. Weitz, University of California, Berkeley; Sally Thompson, University of California Berkeley; Ken Schwab, University of California Berkeley
3:40 PM
 The role of total belowground carbohydrates in resprout survival of chaparral shrubs
R. Brandon Pratt, California State University, Bakersfield; Anna L. Jacobsen, California State University, Bakersfield
4:00 PM
 Differential mortality in chaparral species during California’s 2014 historic drought is related to life history and hydraulic traits
Martin Venturas, California State University; Evan D. MacKinnon, California State University, Bakersfield; Hannah L. Dario, Pepperdine University; Anna L. Jacobsen, California State University, Bakersfield; R. Brandon Pratt, California State University, Bakersfield; Stephen D. Davis, Pepperdine University
4:20 PM
 Ferns living on the edge: Differential traits for survival during California’s historic drought
Helen I. Holmlund, Oklahoma Christian University; Victoria M. Lekson, Pepperdine University; Breahna M. Gillespie, Spelman College; Nicole A. Nakamatsu, Pepperdine University; Amanda M. Burns, Berea College; Jarmila Pittermann, University of California Santa Cruz; Stephen D. Davis, Pepperdine University