DEMONSTRATION OF FLAVONOID ENZYMES IN CYANIC AND ACYANIC PELARGONIUM-ZONALE-HYBRIDS

The cyanic and acyanic colour of Pelargonium cultivars is the result of the presence or absence of anthocyanins in the flowers. Instead of anthocyanins, acyanic flowers contain different types and amounts of flavonoids leading to white or cream colour. Our aim was to demonstrate the enzymes of the anthocyanin pathway and to identify possible blocks in the main enzymatic steps. We investigated four enzymes, chalcone synthase (CHS), flavanone 3s-hydroxylase (FHT), dihydroflavonol 4-reductase (DFR) and flavonol synthase (FLS). The first three enzymes lead to the production of leucoanthocyanidins, the substrates of the anthocyanidin synthase (ANS), and FLS is responsible for flavonol synthesis. In spite of many examples of testing the above enzymes in numerous species, up to now, Pelargonium proved to be a recalcitrant plant for enzymatic studies. Nevertheless, we detected significant differences in enzyme activity between cultivars and between flower developmental stages of the same cultivar. The acyanic cultivars studied seem to be blocked late in the anthocyanin pathway. Our results may serve as a basis for further genetic and biochemical characterisation of Pelargonium plants.