A fascinating new study published in the journal Nature Plants describes a bizarre plant that lives in the dark rain forests of southeast Asia and is able to handle low levels of sunlight by growing up blue instead of green. The “peacock begonia,” scientifici name Begonia pavonina, has developed leaves that are iridescent rather than the typical green, an anomaly that could expand our understanding of how photosynthesis works.

This strange coloring comes from iridoplasts, photosynthetic structures that, like chloropasts, act as the mechanisms for photosynthesis, collecting light and turning it into energy. But scientists found something interesting when looking at Begonia pavonina in detail. The iridoplasts were a very different shape, and were layered on top of each other like pancakes.

So the light that passes through this lens is bent, resulting in an iridescent glow. This enables the plant to absorb all sorts of light in a dark environment under the canopy of the forest. Only blue light is reflected back, which is what we see.

“Enhanced light harvesting is an area of interest for optimizing both natural photosynthesis and artificial solar energy capture,” the paper’s abstract states. “Iridescence has been shown to exist widely and in diverse forms in plants and other photosynthetic organisms and symbioses, but there has yet to be any direct link demonstrated between iridescence and photosynthesis. Here we show that epidermal chloroplasts, also known as iridoplasts, in shade-dwelling species of Begonia, notable for their brilliant blue iridescence, have a photonic crystal structure formed from a periodic arrangement of the light-absorbing thylakoid tissue itself.

“This structure enhances photosynthesis in two ways: by increasing light capture at the predominantly green wavelengths available in shade conditions, and by directly enhancing quantum yield by 5–10% under low-light conditions. These findings together imply that the iridoplast is a highly modified chloroplast structure adapted to make best use of the extremely low-light conditions in the tropical forest understorey in which it is found.”