Effects of blue and red light irradiations on flower colouration in cherry blossom (Prunus x yedoensis 'Somei-yoshino')

摘要

'Somei-yoshino' (Prunus x yedoensis 'Somei-yoshino'), which possesses beautiful large pink flowers, is the most commonly cultivated cherry blossom cultivar in Japan. However, the shoots only produce white flowers when grown indoors, as opposed to the more favourable pink flowers and the physiology of the colour development of this flower has not been studied yet. The pink colour of cherry blossom petals is produced by the pigment anthocyanin, the biosynthesis of which is known to be induced by light irradiation. Therefore, in the present study, we investigated the effects of light conditions, particularly of blue light on colour development and anthocyanin biosynthesis. We found that wavelengths in both the blue and red parts of the spectrum are involved in cherry blossom colouration, for which blue light of 450 nm is considered to be the most effective. Interestingly, monochrome red light irradiation had not affect the anthocyanin biosynthesis; however, irradiation with both blue and red lights induced greater anthocyanin production than irradiation with monochrome blue light, indicating an association between the blue and red light receptors. Our results provide an understanding of a part of the physiology of the colour development of 'Somei-yoshino' cherry blossom.