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Effect of Seasonal Variation on Leaf Cuticular Waxes’ Composition in the Mediterranean Cork Oak (Quercus suber L.)
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Orientador(es)
Resumo(s)
Quercus suber L. (cork oak) leaves were analyzed along one annual cycle for cuticular wax
content and chemical composition. This species, well adapted to the long dry summer conditions
prevailing in the Mediterranean, has a leaf life span of about one year. The cuticular wax revealed a
seasonal variation with a coverage increase from the newly expanded leaves (115.7 g/cm2 in spring)
to a maximum value in fully expanded leaves (235.6 g/cm2 after summer). Triterpenoids dominated
the wax composition throughout the leaf life cycle, corresponding in young leaves to 26 g/cm2
(22.6% of the total wax) and 116.0 g/cm2 (49% of the total wax) in mature leaves, with lupeol
constituting about 70% of this fraction. The total aliphatic compounds increased from 39 g/cm2
(young leaves) to 71 g/cm2 (mature leaves) and then decreased to 22 g/cm2 and slightly increased
during the remaining period. The major aliphatic compounds were fatty acids, mostly with C16
(hexadecanoic acid) and C28 (octacosanoic acid) chain lengths. Since pentacyclic triterpenoids are
located almost exclusively within the cutin matrix (intracuticular wax), the increase in the cyclicto-
acyclic component ratio after summer shows an extensive deposition of intracuticular waxes in
association with the establishment of mechanical and thermal stability and of water barrier properties
in the mature leaf cuticle
Descrição
Palavras-chave
Quercus suber seasonal variation cuticular waxes leaves
Contexto Educativo
Citação
Simões, R.; Miranda, I.; Pereira, H. Effect of Seasonal Variation on Leaf Cuticular Waxes’ Composition in the Mediterranean Cork Oak (Quercus suber L.). Forests 2022, 13, 1236
Editora
MDPI