FLAVONOID DIVERSITY AND METABOLISM IN 10 ROSA-X-HYBRIDA CULTIVARS

The flavonoid metabolism in the petals of more than 100 cyanic cultivars of Rosa X hybrida was analysed by means of spectrophotometric and HPLC techniques. Total anthocyanin of ca 60 mg g(-l) dry wt consisting of various mixtures of cyanidin 3,5-diglucoside and pelargonidin 3,5-diglucoside were observed, while only pure cyanidin 3,5-diglucoside was found to accumulate in amounts above 60 mg g(-1) dry wt. Only small amount of the related 3-monoglucosides were detected and paeonidin 3,5-diglucoside was rarely present. Cultivars producing almost exclusively kaempferol, as well as those dominated by quercetin exhibited chemotypes based mainly on the 3-glucosides, 4'-glucosides and 3-rhamnosides. The possible relative distributions, between cyanidin, pelargonidin, quercetin and kaempferol were determined revealing a range of apparently 'forbidden' co-occurrences. With regard to our enzymatic knowledge of the flavonoid pathway established in other ornamental species, the metabolism of the rose flavonoids is discussed.