engleski

Contribution to Discussions on the Origin of the Green Oak Growing in Northern Dalmatia

The "green oak" growing in Ravni Kotari, near Zadar, Croatia was described as a hybrid Q. x viridis Trinajsti};, hybr. nov., hybrid between Quercus cerris f. austriaca and Q. ilex. It is unlikely to find a hybridization between two species where acorns mature in the second year (Q. cerris L.) and in the first year (Q. ilex L.). Therefore we visited "green oak" repeatedly and described diagnostic features in details. The composition of leaf volatiles of the "green oak" with gas chromatography and gas chromatography/mass spectrometry was analyzed too. Same method was used for investigation of leaf volatiles in leaf samples of supposed parent species Q. cerris and Q. ilex. The volatile fraction obtained by steam distillation of leaves averaged to 0.05 % fresh weight. In total 206 compounds were isolated from all three investigated specimens of which 141 were identified. 128 components were separated in "green oak", 126 in Q. ilex, and 100 in Q. cerris. 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 Quercus ilex and Q. cerris. The opinion is given that the "green oak" could be a progeny of back-crossed hybrid between Q. cerris and Q. suber or a variety of Q. cerris restricted to a small area of distribution in Ravni Kotari, Croatia.

Quercus L.; Q. cerris L.; Q. ilex L.; hybrids; green oak; leaf volatile substances; morphology

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