Abstract
We investigated the relationship between petal brightness under ultraviolet light (365 nm) and flavonoid concentrations using 75 pale color lines of Eustoma grandiflorum. Flavonoid concentrations of the dark color petals were above 10 mg/g f. w., while those of the bright color petals were below 3 mg/g f. w. Several lines showed an image of bright petals with dark edges. A purple picotee petal and a white petal derived from ‘Candy Marin’ also showed such images. The edge tissue contained a 30- times higher concentration of flavonoids than the other tissue in both petals, suggesting that the same mechanism affects the flavonoid distribution. We can roughly estimate flavonoid concentration in pale color petals of Eustoma using this method. This method could be applied to other plants including Dianthus and Petunia. Because information on the flavonoid concentration in many flowers can be obtained immediately and non-destructively, this method could contribute to breeding selection and studies on the regulation of flavonoid-anthocyanin biosynthesis.
