title: Species-specific reversal of stem xylem embolism after a prolonged drought correlates to endpoint concentration of soluble sugars.
abstract: Recent reports on tree mortality associated with anomalous drought and heat have raised interest into processes underlying tree resistance/resilience to water stress. Hydraulic failure and carbon starvation have been proposed as main causes of tree decline, with recent theories treating water and carbon metabolism as interconnected processes. We subjected young plants of two native (Quercus pubescens [Qp] and Prunus mahaleb [Pm]) and two invasive (Robinia pseudoacacia [Rp] and Ailanthus altissima [Aa]) woody angiosperms to a prolonged drought leading to stomatal closure and xylem embolism, to induce carbon starvation and hydraulic failure. At the end of the treatment, plants were measured for embolism rates and NSC content, and re-irrigated to monitor recovery of xylem hydraulics. Data highlight different hydraulic strategies in native vs invasive species under water stress, and provide physiological explanations for species-specific impacts of recent severe droughts. Drought-sensitive species (Qp and Rp) suffered high embolism rates and were unable to completely refill xylem conduits upon restoration of water availability. Species that better survived recent droughts were able to limit embolism build-up (Pm) or efficiently restored hydraulic functionality after irrigation (Aa). Species-specific capacity to reverse xylem embolism correlated to stem-level concentration of soluble carbohydrates, but not to starch content.
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: Dipartimento di Scienze AgroAlimentari, Ambientali e Animali, Università di Udine, Viale delle Scienze 91, 33100 Udine, Italy.
authors.forename: Valentino
authors.initials: V
authors.lastname: Casolo
authors.affiliation: Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy.
authors.forename: Jessica
authors.initials: J
authors.lastname: Luglio
authors.affiliation: Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Bertuzzi
authors.affiliation: Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, Viale Ferdinando Stagno d'Alcontres 31, 98166 Messina, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Trifilo'
authors.affiliation: Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, Viale Ferdinando 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. Electronic address: nardini@units.it.
authors.forename: Andrea
authors.initials: A
authors.lastname: Nardini
mesh_terms: D002241:Carbohydrates / Q000032:analysis*; D055864:Droughts; D019684:Magnoliopsida / Q000502:physiology; D009995:Osmosis; D018515:Plant Leaves / Q000378:metabolism; D018547:Plant Stems / Q000502:physiology*; D012995:Solubility; D013045:Species Specificity; D013227:Steam; D014197:Trees / Q000502:physiology*; D014867:Water / Q000378:metabolism; D052584:Xylem / Q000502:physiology*
chemical_list: D002241:Carbohydrates; D013227:Steam; D014867:Water
keywords: Ailanthus altissima; Non-structural carbohydrates; Prunus mahaleb; Quercus pubescens; Robinia pseudoacacia; Starch; Water potential