Flavonoidmuster als systematisches Merkmal in der Gattung Populus

Buds of almost every species of popular excrete lipophilic “coating” which contains many flavonoid and related derivatives. The compounds found in this “bud coat” of eighty taxa of Populus have been examined and nearly 30 compounds have been identified and their distribution related to the taxonomy of the genus. In sections Aigeiros and Tacamahaca and hybrids of these, chrysin, galangin and pinocembrin form the major components which, in most cases, are accompanied by lesser amounts of tectochrysin, izalpinin, pinostrobin, galangin-3-methylether and pinobanksin-3-acetate. Variations are shown by presence of apigenin and its monomethyl ethers, kaempferol methyl ethers, rhamnetin, quercetin-3,7- and 3,3′-dimethylether, the unusual flavanone “P4” and two chalcones. Myricetin, genkwanin and kaempferol-7.4′-dimethylether are each found only in one species. In the sections Leuce and Leucoides, the major compounds are cinnamic acid derivatives. Flavonoid patterns, as analysed on polyamide TLC, allow species of the sections Aigeiros and Tacamahaca and some hybrids to be characterized, provided several individuals are examined, It is not possible by this method to differentiate clones within a species.