Convergent evolution of disordered lipidic structural color in the fruits of Lantana strigocamara (syn. L. camara hybrid cultivar)

Research conducted:Â The majority of plant colors are produced by anthocyanin and carotenoid pigments, but coloration obtained by nanostructured materials (i.e., structural colors) is increasingly reported in plants. Here, we identify a multilayer photonic structure in the fruits of Lantana strigocamara and compare it to a previously described origin in Viburnum tinus. Methods:Â We used a combination of transmission electron microscopy, serial EM tomography, scanning force microscopy, and optical simulations to characterize the photonic structure in L. strigocamara. We also examine the development of the structure during maturation. Key results:Â We find that the structural color derives from a disordered, multilayered reflector consisting of lipid droplets of ~105 nm that form a plate-like structure in 3D. This structure begins to form early in development and reflects blue wavelengths of light with increasing intensity over time as the structure develops. The lipids used are likely polym...