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| Authors: | I. Kataoka, K. Beppu, T. Yanagi, K. Okamoto |
| Keywords: | anthocyanin, coloration, grapes, light components, visible light, UV |
Abstract:
The contribution of light with different wavelengths to the accumulation of anthocyanins was investigated by using berry sections.
At veraison, the equatorial sections were dissected from softened green berries of ‘Gros Colman’ and were placed in plastic petri dishes containing 0.4 M sucrose.
These sections were thereafter subjected to several light treatments for 72 hr, after which anthocyanin concentration was measured.
Under white and UV fluorescent light, anthocyanins started to accumulate 48 hr after initiating illumination.
After 72 hr, anthocyanin concentration was markedly increased by white light.
Under UV lighting, a considerable amount of anthocyanins also accumulated relative to dark conditions.
As white and UV light intensities increased, anthocyanins gradually increased, but this promoting effect of light on the accumulation of anthocyanin was saturated at 60 μmol m-2 s-1 for white and 0.4 W m-2 for UV. Using LEDs emitting specific wavelengths ranging from the blue to far red regions, the action spectrum for anthocyanin accumulation was determined.
Among the visible light wavelengths, blue light largely enhanced anthocyanin accumulation, as did red and far-red wavelengths, while the green to yellow range was less effective.
These results suggested that the relatively short wavelength band ranging from blue to UV was important for the accumulation of anthocyanins in ‘Gros Colman’ grapes.
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