PIGMENTATION PATTERNS OF MODERN ROSE MUTANTS THROW LIGHT ON THE FLAVONOID PATHWAY IN ROSA X HYBRIDA

The petal flavonoid patterns of four modern rose varieties (Rosa x hybrida) and six of their spontaneous mutants were characterized. Native glycosides of cyanidin, pelargonidin, quercetin and kaempferol were precisely quantified. Mutations could strongly enhance flavonol glycoside (quercetin or kaempferol), as well as anthocyanin concentrations. The increase of the total flavonol concentrations, without changes in the balance between kaempferol and quercetin, also led to new distributions between the different flavonol glycosides. The opening of the pelargonidin route, the decrease of anthocyanin concentration, the modification of the division between mono- and disubstituted flavonoids also arose by mutations. All these changes are discussed with special regard to the current knowledge of flavonoid pathway established in other ornamental species.