The role of defoliation and root rot pathogen infection in driving the mode of drought-related physiological decline in Scots pine (Pinus sylvestris L.)
Aguadé Vidal, David (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Poyatos, Rafael (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Gómez Gallego, Mireia (Centre Tecnològic Forestal de Catalunya)
Oliva, Jonàs (Swedish University of Agricultural Sciences. Department of Forest Mycology and Plant Pathology)
Martínez Vilalta, Jordi, 1975- (Universitat Autònoma de Barcelona. Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia)

Fecha:	2015
Resumen:	Drought-related tree die-off episodes have been observed in all vegetated continents. Despite much research effort, however, the multiple interactions between carbon starvation, hydraulic failure and biotic agents in driving tree mortality under field conditions are still not well understood. We analysed the seasonal variability of non-structural carbohydrates (NSCs) in four organs (leaves, branches, trunk and roots), the vulnerability to embolism in roots and branches, native embolism (percentage loss of hydraulic conductivity (PLC)) in branches and the presence of root rot pathogens in defoliated and non-defoliated individuals in a declining Scots pine (Pinus sylvestris L. ) population in the NE Iberian Peninsula in 2012, which included a particularly dry and warm summer. No differences were observed between defoliated and non-defoliated pines in hydraulic parameters, except for a higher vulnerability to embolism at pressures below -2 MPa in roots of defoliated pines. No differences were found between defoliation classes in branch PLC. Total NSC (TNSC, soluble sugars plus starch) values decreased during drought, particularly in leaves. Defoliation reduced TNSC levels across tree organs, especially just before (June) and during (August) drought. Root rot infection by the fungal pathogen Onnia P. Karst spp. was detected but it did not appear to be associated to tree defoliation. However, Onnia infection was associated with reduced leaf-specific hydraulic conductivity and sapwood depth, and thus contributed to hydraulic impairment, especially in defoliated pines. Infection was also associated with virtually depleted root starch reserves during and after drought in defoliated pines. Moreover, defoliated and infected trees tended to show lower basal area increment. Overall, our results show the intertwined nature of physiological mechanisms leading to drought-induced mortality and the inherent difficulty of isolating their contribution under field conditions.
Ayudas:	Ministerio de Ciencia e Innovación CGL2010-16373 Ministerio de Ciencia e Innovación CSD2008-00040 Ministerio de Educación, Cultura y Deporte FPU-AP2010-4573
Derechos:	Tots els drets reservats.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió acceptada per publicar
Materia:	Die-off ; Fungi pathogen ; Global change ; Hydraulic failure ; Non-structural carbohydrates
Publicado en:	Tree physiology, Vol. 35 Issue 3 (March 2015) , p. 229-242, ISSN 1758-4469

DOI: 10.1093/treephys/tpv005
PMID: 25724949

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Documentos de investigación > Documentos de los grupos de investigación de la UAB > Centros y grupos de investigación (producción científica) > Ciencias > CREAF (Centre de Recerca Ecològica i d'Aplicacions Forestals)
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