Contribution to the knowledge of provenance effect on cork oak (Quercus suber L.) performance within the scope of the Reinfforce Project

Mestrado em Gestão e Conservação dos Recursos Naturais - Instituto Superior de Agronomia / Universidade de Évora

Cork oak (Quercus suber L.) is distributed in the western part of the Mediterranean Basin, occurring across a wide range of environmental conditions and thus, it has the potential to exhibit a larger intraspecific variation in morphological and functional traits. Significant differences among populations of cork oak have been reported for several traits related to acorn size, growth, and functional traits related to leaf pest damage resistance, drought and cold tolerance. The central purpose of this study was to investigate the inter-provenance variability of cork oak in 4-year-old seedlings. This study was carried out at the arboretum of Tapada da Ajuda (planted in 2012) located in Lisbon, Portugal; between January and July 2016. This is within of the Reinfforce’s arboreta network, which aims to address the adaptability of forest species in the European Atlantic region to climate change. The variation in budburst timing, growth, morphological and physiological traits was compared for six contrasting cork oak provenances from the natural distribution area of the species. Regarding timing of budburst, Italian and French (Pyrenees) provenances from the eastern part of the natural range tended to burst earlier than French provenance (Landes) from the western part. Regarding growth, Spanish provenance exhibited one of the lowest total height and Moroccan exhibited one of the lowest basal diameter. Moroccan exhibited one of the lowest height growth during the study period. Both provenances above mentioned exhibited lower increases in basal diameter. Regarding leaf morphology, Moroccan exhibited one of the highest leaf size and specific leaf area. Regarding physiological traits, Moroccan consistently revealed one of the lowest relative and absolute foliar chlorophyll (Chl) content as well as Chl a/b ratio. Seedlings did not exhibit damage at the photosystem II level in January, suggesting that cold-induced photoinhibition of PSII during winter did not occur in this study. All seedlings exhibited signs of photosynthetic decline in mid-March. The Fv/Fm ratio was a good indicator of leaf senescence. The results of the simulation tests of late spring frost were inconclusive. However, Spanish and Italian provenances exhibited low leaf cell membrane injury, determined by relative electrolyte leakage, suggesting lower freezing sensibility. The existence of significant differences among provenances reveals the possibility of selection at the provenance level for (re)forestation actions

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