Fluorescent Flowers Lure Pollinators

The brightly colored flower Mirabilis jalapa (shown, top) is literally a late bloomer, unfurling its petals only in the late afternoon. A new report suggests that the blossom is able to attract pollinators, despite evening's growing darkness, thanks to fluorescent pigments in the plant's petals (Nature 2005, 437, 334). Fernando Gandía-Herrero, Francisco García-Carmona, and Josefa Escribano of Spain's University of Murcia analyzed pigments from M. jalapa's petals and found fluorescence-emitting yellow betaxanthins as well as fluorescence-absorbing violet betacyanins. These pigments combine to create a fluorescent green pattern on the flower's petals (shown, bottom). Because bees and bats have visual receptors that are sensitive to green light, the researchers speculate that the fluorescent patterns lure these potential pollinators. Fluorescent signaling is an unusual mode of communication among plants and animals, having been observed previously only in budgerigars and mantis shrimp. The Murcia group's finding is the first report of plants using fluorescence to communicate.