Quantitative Evaluation of the Contribution of Four Major Anthocyanins to Black Flower Coloring of Dahlia Petals

Abstract

The black flower color of dahlias (Dahlia variabilis) has been suggested to be attributed to a high accumulation of cyanidin (Cy)-based anthocyanins. A possible explanation for this effect is that Cy-based anthocyanins in dahlias contribute more to the black flower color than pelargonidin (Pg)-based anthocyanins by lowering petal lightness (L*) and chroma (C*), but no obvious evidence has been reported. In this study, four major anthocyanins accumulated in dahlia petals, 3,5-diglucoside (3,5diG) and 3-(6''-malonylglucoside)-5-glucoside (3MG5G) of Pg and Cy, were purified and their colors were evaluated in vitro at various pHs ( , suggesting that Cy 3MG5G contributed more than Pg 3MG5G. A similar tendency was observed in the color measurement of mixed anthocyanins in various proportion of Pg and Cy. The L* and C* of Pg 3MG5G were much higher than those of the other three anthocyanins; therefore, its color was considered to be the farthest from black among the four anthocyanins. The accumulated amount of 3MG5G-type anthocyanins was much higher than that of 3,5diG-type anthocyanins in all nine cultivars, although the proportion of Pg-and Cy-based anthocyanins varied among the cultivars. Considering these results, it was suggested that because 3MG5G-type anthocyanins predominantly accumulate in petals, and Cy 3MG5G has a significantly higher contribution to lowering L* and C* than Pg 3MG5G, the high accumulation of Cy-based anthocyanins is critical for the black flower coloring of dahlias. The contribution of each anthocyanin is considered to depend on the structure; therefore, identifying the anthocyanin with the highest contribution to lowering L* and C* may enable the production of black flowers in various species through the high accumulation of the anthocyanin in petals.

Post-transcriptional silencing of chalcone synthase is involved in phenotypic lability in petals and leaves of bicolor dahlia (Dahlia variabilis) ‘Yuino’

“…3). Analysis of the crude extracts showed that the retention time of the peaks of anthocyanins in red single-colored petals and the red part of bicolor petals was the same as in 'Kokucho' petals (data not shown), which mainly accumulate pelargonidin 3-(6''-malonylglucoside)-5glucoside and cyanidin 3-(6''-malonylglucoside)-5-glucoside (Deguchi et al 2016).…”

Identification of anthocyanic profile and determination of antioxidant activity of Dahlia pinnata petals: A potential source of anthocyanins

“…Regarding color intensity, EPAA presented the highest values in L* (lightness), a* (redness), and b* (yellowness), for a bright red/yellow tone (L* = 26.81, a* = 59.47, b* = 45.72), while in the case of EPMA, the color was red/blue (dark red) without brightness (L* = 2.15, a* = 12.90, b* = 3.28), resulting in an intense dark color (Table 3). Coordinates for L*, a*, and b* with a tendency to red color have been previously reported for purified fractions of anthocyanin solutions at pH 3 and measured immediately after dilution from different dahlia cultivars (around 70, 30.14, and 16.62, respectively) (Deguchi et al, 2016). On the other hand, the coordinates of EPAA extract show greater similarity to the L* and a* coordinates reported for the Red 40 L*(45.74), a*(45.14), b*(10.58) (Hernández-Martínez et al, 2017), which also indicates a brilliant red hue.…”

Information on Flower Coloration and Pigmentation in Current Carnation Cultivars for Use in Future Flower-color Breeding

“…78) displaying black coloration in the variegation that accumulated the largest TA than the other cyanic cultivars (Tables 1 and 2). The black-colored carnation flowers are likely due to the high concentration of Cy-based anthocyanin the same as in blackflowered dahlias (Deguchi et al, 2016). Interestingly, there were no cultivars composed of Cy-based anthocyanins with Ch2'G as the major flower pigment, which yields a maroon flower color (Yamaguchi, 1989).…”

“…Previously, Yamaguchi (1992) introduced an interspecific hybrid of D. caryophyllus and other Dianthus species with flowers possessing center spots and base parts accumulating Cy-based and Pg-based anthocyanins, respectively. There are some ornamental flowers that accumulate both Pg-and Cy-based anthocyanins as major flower pigments and the varying ratios of Pg and Cy extend the flower color range (Iwata et al, 1985;Torskangerpoll et al, 2005;Deguchi et al, 2016). However, carnation cultivars accumulate either Pg-or Cy-based anthocyanin dominantly.…”