With their shiny metallic color, the blue fruits of the Lorsteinus shrub (Viburnum tinus), A flower plant popular in gardens throughout Europe, is a sight to behold. But it is the surface that attracts the attention of scientists in a new study.
Researchers viewed fruit tissue samples through an electron microscope to examine their internal structure. They found that no blue pigment is typical of other blueberries such as blueberries – just layers and layers of blob. These drops turned out to be small droplets of fat, arranged in a way that reflected blue light — a phenomenon known as “structural color” —in the team report today Current biology.
Beneath the fat droplets is another layer of dark red pigment, which absorbs any other wavelength of light and intensifies the blue shade. The team verified these findings using computer simulations, confirming that this type of structure could actually produce the exact shade of blue seen in Laurstinus.
The striking color of laurstinus fruit may indicate its high fat content to birds. Although the structural color in animals is well documented, including vibrant peacock feathers and delicate butterfly feathers, it is rarely seen in plants. What’s more, this is the first time that fat has been found responsible for this mechanism. The team suspects it may be more widespread, and hopes to identify this type of structure in other species.