title: X-ray microtomography observations of xylem embolism in stems of Laurus nobilis are consistent with hydraulic measurements of percentage loss of conductance.
abstract: Drought-induced xylem embolism is a serious threat to plant survival under future climate scenarios. Hence, accurate quantification of species-specific vulnerability to xylem embolism is a key to predict the impact of climate change on vegetation. Low-cost hydraulic measurements of embolism rate have been suggested to be prone to artefacts, thus requiring validation by direct visualization of the functional status of xylem conduits using nondestructive imaging techniques, such as X-ray microtomography (microCT). We measured the percentage loss of conductance (PLC) of excised stems of Laurus nobilis (laurel) dehydrated to different xylem pressures, and compared results with direct observation of gas-filled vs water-filled conduits at a synchrotron-based microCT facility using a phase contrast imaging modality. Theoretical PLC calculated on the basis of microCT observations in stems of laurel dehydrated to different xylem pressures overall were in agreement with hydraulic measurements, revealing that this species suffers a 50% loss of xylem hydraulic conductance at xylem pressures averaging -3.5 MPa. Our data support the validity of estimates of xylem vulnerability to embolism based on classical hydraulic techniques. We discuss possible causes of discrepancies between data gathered in this study and those of recent independent reports on laurel hydraulics.
authors.affiliation: Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Nardini
authors.affiliation: Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy.
authors.forename: Tadeja
authors.initials: T
authors.lastname: Savi
authors.affiliation: Institut für Botanik, Universität Innsbruck, Sternwarterstrasse 15, A-6020, Innsbruck, Austria.
authors.forename: Adriano
authors.initials: A
authors.lastname: Losso
authors.affiliation: Dipartimento Territorio e Sistemi Agro-forestali, Università degli Studi di Padova, Viale dell'Università 16, 35020, Legnaro (PD), Italy.
authors.forename: Giai
authors.initials: G
authors.lastname: Petit
authors.affiliation: Dipartimento di Ingegneria e Architettura, Università di Trieste, Piazzale Europa 1, 34127, Trieste, Italy.|Elettra-Sincrotrone Trieste, Area Science Park, 34149, Basovizza, Trieste, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Pacilè
authors.affiliation: Elettra-Sincrotrone Trieste, Area Science Park, 34149, Basovizza, Trieste, Italy.
authors.forename: Giuliana
authors.initials: G
authors.lastname: Tromba
authors.affiliation: Institut für Botanik, Universität Innsbruck, Sternwarterstrasse 15, A-6020, Innsbruck, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Mayr
authors.affiliation: Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche e Ambientali, Università di Messina, Salita F. Stagno D'Alcontres 31, 98166, Messina, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Trifilò
authors.affiliation: Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche e Ambientali, Università di Messina, Salita F. Stagno D'Alcontres 31, 98166, Messina, Italy.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Lo Gullo
authors.affiliation: Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy.
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Salleo
mesh_terms: D027442:Laurus / Q000502:physiology*; D018547:Plant Stems / Q000502:physiology*; D014867:Water / Q000502:physiology*; D055114:X-Ray Microtomography; D052584:Xylem / Q000033:anatomy & histology / Q000502:physiology*
chemical_list: D014867:Water
keywords: X-ray microtomography (microCT); embolism; hydraulics; laurel (Laurus nobilis); percentage loss of conductance (PLC); synchrotron; xylem