EPICUTICULAR WAXES OF SEDUM SERIES RUPESTRIA

Epicuticular waxes from 55 plants of the seven species of Sedum series Rupestria and four artificial hybrids have been examined by GC and GC-MS. The taxa were S. amplexicaule, S. forsterianum, S. montanum ssp. montanum, S. montanum ssp. orientale, S. ochroleucum, S. pruinatum, S. rupestre ssp. erectum, S. rupestre ssp. rupestre, S. sediforme, and four hybrids between S. forsterianum and S. rupestre ssp. erectum. Alkanes, alcohols, aldehydes, triterpenoids and wax esters were the main wax components. Comparison of wax composition and wax ultrastructure of glaucous and glossy plants led to the conclusion that triterpenoids are primarily responsible for glaucousness. Some 14 triterpenes were detected, the major being germanicyl formate, fern-8-en-3-yl formate, taraxerone and taraxeryl acetate. Fern-8-en-3-yl formate was isolated from S. forsterianum. The distribution of triterpenes generally supported the phylogeny of the species based on a combination of biosystematic and molecular data, but failed to provide additional evidence for the presumed allopolyploid origin of S. rupestre ssp. rupestre from S. forsterianum and S. rupestre ssp. erectum.