Summer and winter can equally stress holm oak (Quercus ilex L.) in Mediterranean areas: A physiological view
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Date
2022
Authors
Martín Sánchez, RubénPeguero Pina, José Javier
Alonso Forn, David
Ferrio Díaz, Juan Pedro
Sancho Knapik, Domingo
Gil Pelegrín, Eustaquio
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Typology
articleArticle
Abstract
Q. ilex is a circum-Mediterranean species which must deal with two stressful periods throughout the year: summer and winter. However, the intensity of these abiotic stresses is very variable depending on the specific area of its distribution range. Besides, two subspecies are usually distinguished, even sometimes recognised as two different true species. Nevertheless, differences in the response to both summer and winter stresses among populations overstep the purely taxonomic question. Regarding to temperature, this species has shown a high resistance to both extremes. On the one hand, critical temperature at leaf level has been estimated in 50.2 °C for a provenance in the Iberian Peninsula (Soria, Spain), a temperature which even in the hottest areas of its distribution range is hardly ever reached. On the other hand, minimal temperature for the survival of the leaves has been estimated in −19.8 °C for Italian provenances and -26.6 °C for one of the coldest provenances (Soria, Spain). Similarly, these temperatures are quite rarely reachable in their respective provenances. Concerning to summer-drought, this may compromise xylem stability in severe cases of scarcity of water in the soil, inducing cavitation when water soil potential is too negative. In this sense, Q. ilex has demonstrated to have a high resistance to cavitation, represented by quite negative values of P50 and P88 when compared to other species. Besides, Iberian provenances (i.e. the most continental ones) have shown a higher resistance to cavitation than French or Italian ones. Likewise, holm oak may suffer cavitation during winter, but in this case by a completely different factor: freezing-thawing cycles. Winter-cavitation seems to be related to vessel size, with wider vessels being more vulnerable to cavitate than narrower ones. In spite of its paleotropical origin, Q. ilex has achieved to develop multiple adaptations and physiological strategies that has enabled it not only to withstand the hard climatic conditions imposed by Mediterranean climate, but to colonize and even dominate great part of the Mediterranean landscape.
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Bibliographic citation
Flora, 2022, 290, 152058
AGROVOC subjects
SequíaClima mediterráneo
Quercus ilex
Other field subjects
Drought toleranceENERGY-DISSIPATION
Frost
Functional traits
mediterranean-type climates
PHOTOSYNTHETIC ACTIVITY
Quercus ilex
REFLECTANCE INDEX
STOMATAL RESPONSES
water relations
WOODY-PLANTS
XANTHOPHYLL CYCLE
Xylem-cavitation
Clima
Drought
frost
INDUCED XYLEM CAVITATION
Mediterranean-type climates
Quercus
Quercus ilex
Xylem-cavitation
Sponsorship
This research was funded by Grant PID2019-106701RR-I00 funded by MCIN/AEI/ 10.13039/501100011033 and by Gobierno de Aragón H09_20R research group. Work of D.A-F. is supported by an FPI-INIA contract BES-2017-081208 and work of R.M-S. is supported by a pre-doctoral Gobierno de Aragón scholarship.