Floral coloration and pigmentation in Calibrachoa cultivars

Abstract

SummaryThe ¯oral pigment pro®les of twenty in Calibrachoa cultivars were determined and compared with the pro®les of selected Petunia cultivars. Calibrachoas could be divided into two groups based on high (177±871.mgg±1 FW) and low 2±9.mg g±1 FW) carotenoid content; the groups were represented by yellow and white ¯owers, respectively. In addition to yellow cultivars, the high carotenoid content group included vivid-red and vivid-purplish-red cultivars that were characterized by a low ¯oral pH of 4.5±4.8 and accumulation of delphinidin and petunidin, respectively, as the major ¯oral anthocyanidin. In addition to cultivars with white ¯owers, the low carotenoid content group contained vivid-purple and vivid-red-purple cultivars that were characterized by higher (pH 5.4±5.7) and intermediate (pH 4.8±5.3) corolla pHs, respectively, and accumulation of malvidin. The strategies of calibrachoas and petunias for expressing yellow and red ¯owers were found to differ. For yellow ¯owers, calibrachoas use carotenoids, whereas petunias use ¯avonols plus carotenoids. For red ¯owers, calibrachoas use carotenoids, delphinidin and lower corolla pH, whereas petunias use cyanidin and lower corolla pH.