Studies on the Flower Colours of the Sweet Pea

By the applications of paper chromatographic and spectrophotometric techniques quantitative and qualitative studies were made of developmental changes in the anthocyanidins in the flowers of the spring-flowering sweet pea. From the time the anthocyanin formation occurred, petals grew in weight exponentially until they reached their senescence. The logarithm of petal fresh weight increased linearly with time and served as a convenient morphological index to relate the progress of anthocyanin synthesis.The maximum relative anthocyanidin concentrations (optical density at λ maximum/ mg dry weight) were generally attained by the petals approximately 6 days after the initiation of anthocyanin synthesis, namely, the most rapid anthocyanin formation occurred after flower opening.Of the six kind of anthocyanidins identified, delphinidin, petunidin and malvidin were found in the deep purple or lavender coloured cultivars, cyanidin and peonidin were found in the deep red or deep pink coloured cultivars and pelargonidin was found in the salmon coloured cultivar. Furthermore, in the scarlet coloured cultivar pelargonidin, cyanidin and peonidin were found. And the relative contents of pelargonidin: cyanidin: peonidin in mature petals of the last cultivar was about 67: 12: 21.