Fig. 2. The chromatogram of flavonoids in petals of Malus and the identification of kaempferol glycosides.

a The HPLC chromatogram of flavonoids detected at 365 nm (M. baccata, white flower genotype; M. ‘Royalty’, red flower genotype; WT, M. domestica ‘Royal Gala’; A1/3, the MYB10 overexpressed transgenic line of ‘Royal Gala’). b Structures of kaempferol glycosides. c ESI-MS spectra of three kaempferol glycosides at positive mode. C1: cyanidin 3-O-galactoside; Q1: quercetin 3-O-galactoside; Q2: quercetin 3-O-glucoside; Q3: quercetin 3-O-xyloside; Q4: quercetin 3-O-arabinoside; Q5: quercetin 3-O-rhamnoside; K1, kaempferol 3-O-xyloside; K2, kaempferol 3-O-arabinoside, and K3, kaempferol 3-O-rhamnoside