Scientists may have finally discovered why peacock begonias have their leaves colored in that vibrant metallic shade of blue. Natural wonders are everywhere and, the more we find scientific explanations for them, the better they become.
A research paper, published Oct. 24 in Nature Plants by Heather Whitney and her colleagues at the University of Bristol in the UK, suggests that the very beauty of this peculiar plant has an evolutionary purpose: the dazzling iridescence may be a way of enhancing photosynthesis in deep shade.
The leaves of begonias are typically dark green; however, if looked at from the right angle, they reveal their metallic blue facet.
"It's like green silk, shot through with a deep royal blue," explained Whitney.
From butterflies to pigeons, peacocks and jewel beetles, this natural occurrence isn't that uncommon. The body parts are not a matter of pigments and color per se, but the result of microscopic structures that reside in the evenly spaced layers. As light gets to each layer, some of it is reflected and the rest of it passes through. As it turns out, the regular gaps amplify each other to produce marvelous, bright colors. The scientific name for this phenomenon is iridescence.
"It's actually quite brilliant. Plants have to cope with every obstacle that's thrown at them without running away. Here we see evidence of a plant that's actually evolved to physically manipulate the little light it receives," said Whitney. "It's quite amazing, and was an absolutely surprising discovery."
Inside the begonias' chloroplasts, the team found thylakoids, visually similar to minuscule towers -structurally perfect, in the case of begonias - and serving the functional purpose of turning light into chemical energy. Usually, the thylakoids are random and lack a distinct shape, but their placement inside begonias is a matter of outstanding cellular architecture.
What this amazing discovery proves is that, instead of reflecting all the light they receive, the leaves absorb green and reflect blue entirely, which is the opposite of what usually happens in plants' leaves. Because of the thylakoids' structures, light physically slows down in front of the very thick pattern alignment, which works like a dense crystal.
In quantum physics, slow light is the effect of light diminishing in speed as it passes through matter of various densities. In begonias, this effect increases the photosynthesis up to 10 percent.
Iridescent Fauna
Butterflies are among the most fascinating species that have amazed people for more than a millennia, and whose anatomy has been explained in a number of different ways. Similar to begonias, some butterflies have gorgeous metallic blue wings like the blue morpho butterfly, found in the rainforests of South America.
Buprestidae is a family of beetles that has the same characteristic as begonias and butterflies. Because of their magnificent colors, the beetles' elytra or forewings have been traditionally used in creating jewelry in some Asian countries.
Another example of the magnificence of iridescence, one that you don't have to wander in nature to come across, are pigeons. You'll find them in virtually any big city; their feathers (especially around the neck) have the same structural composition described above.
Last but not least is the peacock, after which the begonia is named, and which is considered to be the king of natural iridescence among animals. Its magnificence comes from the minuscule bowl-shaped indentations causing this effect on its feathers.
