Characteristics of Color Development and Relationship between Anthocyanin Synthesis and Phenylalanine Ammonia-lyase Activity in ^|^lsquo;Starking Delicious^|^rsquo;, ^|^lsquo;Fuji^|^rsquo; and ^|^lsquo;Mutsu^|^rsquo; Apple Fruits

Abstract

To elucidate the characteristics of color development in apple cvs ‘Starking Delicious’ (‘SD’), ‘Fuji’ and‘ Mutsu’, the effeccts of light on anthocyanin synthesis and L-phenylalanine ammonia-lyase (PAL) activity were investigated. Irradiation with white light and simultaneous irradiation with white and ultraviolet light with an emission peak at 312nm (white+UV 312) were used. When the whole fruit skin was examined, ‘SD’ produced higher anthocyanin levels than ‘Fuji’especially under white light. In skin disks, however, anthocyanin synthesis was increased in ‘Fuji’to the same level as in ‘SD’. The yellow-colored cultivar, ‘Mutsu’, did not respond to white light, and only produced a small amount of anthocyanin under white+UV 312 light. In whole fruit skin at least, there was a close correlation between anthocyanin synthesis and PAL activity. In skin disks, PAL activity was far higher than in whole fruit skin, however, anthocyanin synthesis did not show a similar increase in PAL activity. In ‘Mutsu’, white light did not induce anthocyanin synthesis although it stimulated PAL activity to the same extent as the white+ UV 312 light.