Journal Article

Hydraulic traits are associated with the distribution range of two closely related Mediterranean firs, <i>Abies alba</i> Mill. and <i>Abies pinsapo</i> Boiss.

José Javier Peguero-Pina, Domingo Sancho-Knapik, Hervé Cochard, Gonzalo Barredo, Dido Villarroya and Eustaquio Gil-Pelegrín

Edited by Frederick Meinzer

in Tree Physiology

Volume 31, issue 10, pages 1067-1075
Published in print October 2011 | ISSN: 0829-318X
Published online September 2011 | e-ISSN: 1758-4469 | DOI: http://dx.doi.org/10.1093/treephys/tpr092
Hydraulic traits are associated with the distribution range of two closely related Mediterranean firs, Abies alba Mill. and Abies pinsapo Boiss.

Show Summary Details

Preview

Abies alba and Abies pinsapo are two closely related fir species that occur in the Iberian Peninsula under very different environmental conditions. Abies alba proliferates in the humid European mountains, including the Spanish Pyrenees. In contrast, A. pinsapo is a relict species that occurs in some restricted areas of the Mediterranean mountain ranges in Spain and Morocco, which experience intense summer drought periods. To cope with the high atmospheric evaporative demand during summer, A. pinsapo may either have a high resistance to xylem cavitation or develop a very efficient conducting system to reduce the soil-to-leaf water potential gradient. To investigate such hypotheses, we measured (i) the xylem vulnerability to cavitation for different populations, and (ii) several anatomical and hydraulic parameters indicating xylem sufficiency for ­supplying water to the shoot in two contrasting populations of both species. Our results show that the resistance to cavitation was not different between species or populations. However, hydraulic conductivity (Kh), specific hydraulic conductivity (Ks), leaf-specific conductivity (LSC) and whole-shoot hydraulic conductance (Kshoot) were higher in A. pinsapo, indicating a higher efficiency of water transport, which should contribute to maintaining its xylem tension below the threshold for rapidly increasing cavitation. The higher Ks in A. pinsapo was largely a result of its wider tracheids, suggesting that this species may be much more vulnerable to freeze–thaw-induced cavitation than A. alba. This is consistent with the absence of A. pinsapo in northern mountain ranges with cooler winters. These physiological differences could partly explain the niche segregation and the geographical separation of these two firs.

Keywords: cavitation; summer drought; water potential; winter frost

Journal Article.  5267 words.  Illustrated.

Subjects: Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.