Cell wall sited flavonoids in lisianthus flower petals

Flavonoids are considered to be located predominantly in the vacuoles of ep idermal cells and in the cuticular wax of terrestrial plants. However, rece nt reports have suggested that flavonoids may also reside elsewhere in the cells of green leaves. In the present study of lisianthus flower petals, it is demonstrated that ca. 30% of the whole petal flavonol glycosides are lo cated in the cell wall. These flavonol glycosides are distinguished from th e vacuolar glycosides in that they lack acylation. Evidence from light and confocal microscopy studies is corroborated by HPLC analyses of isolated pr otoplasts and cell wall digests, these having been produced by enzymic trea tment of epidermal peels. This is the first report of the occurrence of fla vonoids in petal cell walls, and it describes novel methodology for such st udies. (C) 2000 Elsevier Science Ltd. All rights reserved.