Anthocyanins of the genus of Hosta and their impacts on tepal colors

Abstract

Currently flower color in Hosta is limited to purple and white with some variation across species and cultivars in patterning of the two colors. This study was undertaken to determine the contributions of anthocyanins to current Hosta flower colors and to investigate the potential for increasing color diversity. Eighty-six hostas (6 species and 80 cultivars) were used in this study to investigate the composition and content of anthocyanins by high-performance liquid chromatography coupled with diode array detection (HPLC-DAD) and high-performance liquid chromatographic with electro spray ionization and mass spectrometry (HPLC–ESI–MS). The results showed that the color variation was low in the tepals of the genus of Hosta. Nine anthocyanins were initially identified using a typical purple cultivar (H. ‘Nakaimo’) and a white species (Hosta montana) The anthocyanins were delphinidin 3,5-O-diglucoside (Dp3G5G), cyanidin 3,5-O-diglucoside(Cy3G5G), petunidin 3,5-O-diglucoside (Pt3G5G), peonidin 3-O-rutinoside-5-O-glucoside (Pn3Ru5G), malvidin 3-O-rutinoside-5-O-glucoside (Mv3Ru5G), malvidin 3,5-O-diglucoside (Mv3G5G), petunidin 3-O-rutinoside (Pt3Ru), peonidin 3-O-rutinoside (Pn3Ru) and malvidin 3-O-rutinoside (Mv3Ru). Anthocyanin types and content were different between the purple flowered hostas (PFH) and the white flowered hostas (WFH, including white flower with purple spots or streaks): PFH had higher levels of anthocyanins and were correlated with the pigments Mv3Ru5G, Mv3G5G, Pt3G5G and Dp3G5G; WFH had lower levels of anthocyanins and were correlated with the pigments Pt3Ru, Pn3Ru, Mv3Ru and Pn3Ru5G. The dominance of Mv3G5G and Mv3Ru5G was responsible for flowers of simplex purple. Path analysis showed that Mv3G5G had the highest direct effect on lightness (L*), and color balance (a* and b*), while Pt3G5G had the highest direct effect on saturation (C*).