This Glowing Blue Plant Hides a Secret in Surviving in the Dark
A paper revealing the shimmering blue peacock begonia (Begonia pavonina) in the dark rain forests of Southeast Asia has been featured in the journal Nature Plants. Adjusting to the minimal amount of sunlight that reaches it, the Begonia pavonina has adapted by developing leaves that seem to glimmer blue in the dim forests.
Most plants rely on chlorophyll to synthesize molecules after collecting light that they could store as energy. Chlorophyll is the pigment that absorbs red and blue light, then reflecting green, resulting in the green that we associate with most plants.
In an interview with the Washington Post, Heather Whitney, an expert in plant surface interactions at the University of Bristol in England and co-author of the paper, explained that this extraordinary coloring is produced by photosynthetic structures called iridoplasts. Collecting light to synthesize molecules that store energy, these structures provide the cellular machinery for photosynthesis.
Upon examining the Begonia pavonina, Whitney observed that the iridoplasts had a very unusual shape. Membranes were layered on top of each other, separated by a thin film of liquid. This layering results in any light that strikes the iridoplasts to bend repeatedly and creates a very remarkable luster. "The light that is passing through gets slightly bent -- it's called interference," Whitney said. "So you have this sort of iridescent shimmer."
Iridoplasts absorb the low levels of sunlight that were available in the dim forests. In the absence of long wavelengths like red and green, blue light is the one that gets reflected back. According to Whitney, this unusual color provides proof of plants' astonishing adaptability. Without the ability to relocate when conditions are less than ideal, plants must find other ways to adapt to their environment.
Because they are unable to move when conditions are unfavorable, they must find other ways of adapting to the world around them. Often, that adaptation is chemical, like the evolution of a purple photosynthetic chemical on early Earth, which was well suited to the wavelengths of light that were available at the time.
"But plants aren't just factories," Whitney asserted, refuting that plants are unable to change or improve their equipment with the passing of time. Iridoplasts show that plants can change their mechanism, allowing them not only to survive but also to thrive.