Effect of Seasonal Variation on Leaf Cuticular Waxes’ Composition in the Mediterranean Cork Oak (Quercus suber L.)

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 Mediterranean, has a leaf life span of about year. The revealed seasonal variation with coverage increase from newly expanded (115.7 µg/cm2 spring) maximum value fully (235.6 after summer). Triterpenoids dominated composition throughout cycle, corresponding young 26 (22.6% total wax) 116.0 (49% mature leaves, lupeol constituting 70% this fraction. aliphatic compounds increased 39 (young leaves) 71 (mature then decreased 22 slightly during remaining period. major fatty acids, mostly C16 (hexadecanoic acid) C28 (octacosanoic chain lengths. Since pentacyclic triterpenoids are located almost exclusively within cutin matrix (intracuticular wax), cyclic-to-acyclic component ratio shows an extensive deposition intracuticular waxes association establishment mechanical thermal stability water barrier properties cuticle.