THE BASIS OF YELLOW COLORATION IN LATHYRUS-APHACA FLOWERS

Flavonol glycosides which constitute 12.7% dry wt of the yellow petals of Lathyrus aphaca consist primarily of larycitrin and syringetin 3-O -rutinoside-7-O-beta-D-glucopyrano sides which are fully characterized here for the first time. These are accompanied by low levels of the k aempferol, quercetin and isorhamnetin analogues and the respective 3-O -rutinosides. The petal absorption spectrum is not produced from the f lavonol glycosides alone, even after variation of concentration, pH, i onic strength and inclusion of metal ions. It is concluded that the ye llow colour of L. aphaca flowers can be accounted for by the superimpo sition of the flavonol absorption, on that of the 1% dry wt of co-occu ring carotenoids when diffused by the highly papillate petal surface.