• Korean Journal of Environment and Ecology
• /
• v.28 no.5
• /
• pp.574-587
• /
• 2014

In this study, vertical distribution patterns of Quercus mongolica Fisch. ex Ledeb. and Q. serrata Murray in Korea were recognized and possibility of introgressive hybridization and gene flow between Q. mongolica and Q. serrata in Mt. Jiri was inferred by flavonoid analyses. The most critical factor on distribution patterns was the altitude in accordance with temperature condition. A zonal distribution was recognized: Quercus mongolica zone in the upper area and Q. serrata zone in the lower area. In Central Korea, the range of vertical distribution of Q. mongolica was above alt. 100m, almost everywhere, whereas that of Q. serrata was from alt. 0 m to alt. 500(-700) m, and the species is rare above that altitude. But in Southern Korea, Q. serrata is found up to above alt. 1,000 m, whereas frequency of Q. mongolica reduces as elevation in decline and the species is rare below alt. 300 m, even though pure stands being formed on higher mountain slope. Altitudinal distribution of the two species, however, overlaps, where the two species occur together. Thirty-seven individuals of Q. mongolica and Q. serrata in Mt. Jiri and other area were examined for leaf flavonoid constituents. Twenty-three flavonoid compounds were isolated and identified; they were glycosylated derivatives of the flavonols kaempferol, quercetin, isorhamnetin, myricetin, and four compounds among the flavonoid compounds were acylated. Kaempferol 3-O-glucoside, quercetin 3-O-glucoside, quercetin 3-O-galactoside and its acylated compounds were major constituents and present in all individuals. Quercus mongolica is distinguished from Q. serrata by the presence of quercetin 3-O-arabinosylglucoside and by high concentration of three acylated compounds, acylated kaempferol 3-O-glucoside, quercetin 3-O-glucoside, quercetin 3-O-galactoside, and by relatively low concentration or lacking of rhamnosyl flavonol compounds. There are intraspecific variations in flavonoid profiles for Q. mongolica and Q. serrata, the flavonoid profiles for individuals of two species in hybrid zone (sympatric zone) tend to be similar to each other, qualitatively and quantitatively. These findings strongly suggest that gene exchange or gene flow occurs through the introgressive hybridization between Q. mongolica and Q. serrata in Mt. Jiri. Therefore, Quercus crispula, occupying morphologically intermediate position between Q. mongolica and Q. serrata, is suspected of being a hybrid taxon of two putative parental species.