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Advisor(s)
Abstract(s)
threatened
by the increasing water deficits related to climate change. To contribute to the understanding of
the capacity of these oaks to withstand severe drought we assessed the vulnerability to xylem embolism
and the anatomical traits in current-year shoots. Data were collected in mature trees at two sites, in central/
coastal and southern/inland Portugal. In situ safety margins to hydraulic failure were evaluated from
long-term predawn and midday leaf water potential records. Results showed that xylem vulnerability to
embolism was similar in Q. ilex and Q. suber. The 50% loss in hydraulic conductivity (Wxyl,50PLC) was
observed at xylem water potentials of 2.9 and 3.2 MPa in shoots of Q. suber and Q. ilex, respectively.
Values of mean vessel diameter of Q. suber shoots at both sites suggest an intra-species adaptation to
the local water availability, with larger vessels at the more mesic site. In situ hydraulic safety margins
observed in shoots showed that, even during the driest periods, both oaks lived comfortably above the
most critical embolism thresholds. However, the hydraulic safety margins were narrower in the driest
site. Results are relevant to the understanding of survival, growth, and functional behaviour of evergreen
oaks in Mediterranean climates, under recurrent/seasonal drought conditions
Description
Keywords
Quercus suber Quercus Ilex vulnerability curves hydraulic conductivity xylem anatomy hydraulic safety margins
Pedagogical Context
Citation
"Forest Ecology and Management". ISSN 0378-1127. 285 (2012) 1-10
Publisher
Elsevier