engleski

Investigation of volatile compounds in a "Green oak" in Croatia

The composition of leaf volatiles of the "Green oak", a supposed hybrid between Quercus cerris and Q. ilex, was investigated with gas chromatography and chromatography/mass spectrometry. The volatile fraction obtained by steam distillation of leaves amounted to 0.05 % fresh weight. 128 components were separated, of which 89 (comprising 85.5 % w/w of the sample) were positively identified and 3 partially characterized. Forty-one substances could be assigned to terpenoids: 24 monoterpenes (6.5 %), 7 sesquiterpenes (8.1 %), beta-cyclohomocytral (0.1 %), 8 C13-norisoprenoids (4.7 %) and the diterpene phytol (2.7 %). A part of the detected substances, like n-alkanes (15.5 %), l-alkenes (0.5 %), and free fatty acids (6.2 %) originated from epicuticular lipids. Aldehydes (27.3 %) included short chain n-alkanals (C6 - C10) and the most abundant single compound trans 2-hexenal (23.3 %). Further substances were the phenols methylsalicylate, eugenol, and cis-isoeugenol and some other minor compounds. Cluster analysis of the patterns of volatiles in leaves of the "Green oak", Quercus ilex and Q. cerris did not support the assumption that the "Green oak" is a hybrid between Q. ilex and Q. cerris.

"Green oak"; Quercus cerris L.; Quercus ilex L.; hybrids; stem distillation of leaves; volatile compounds; cluster analysis

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