This African fruit is nature's shiniest living thing
The tiny metallic fruits of <i>Pollia condensata</i> might look hypnotically delicious, but don't be fooled: They have zero nutritional value.
Tue, Sep 11 2012 at 9:43 PM
An obscure African berry has been declared the shiniest thing in nature by researchers studying the reflectivity of biological tissues, reports the Smithsonian. The iridescent skins of these fruit, which grow from the Pollia condensata plant, even beat out the kaleidoscopic wings of the Morpho butterfly and the exoskeleton of the scarab beetle in shininess.
Though while the Pollia condensata berry might look delectable, there's a catch. It turns out its shininess is just nature's way of compensating for the fruit's exceptionally poor nutritional value and unpalatable taste. In other words, you'd be remiss to judge this berry by its cover.
Scientists speculate that its brilliant colorization attracts birds that may be tricked into dispersing the seeds by either incorrectly believing it to be a juicy meal or by collecting it to decorate their nests or to attract a mate. By doubling down on shininess, Pollia condensata also saves on the energy it would take to give its fruit a juicy, nutritious flesh.
Perhaps the most fascinating aspect of this fruit's iridescence, though, is how it accomplishes its luminous look. Most plants get their color from pigments. For instance, the greenness of most plants comes from the pigment chlorophyll, which is important to photosynthesis. But this berry's fruits contain no pigments. Instead, they achieve their shininess thanks to something called "structural coloration" — a phenomenon that is virtually unheard of in plants.
Basically, the cellulose that makes up the fruit's skin is structured in asymmetrical layers that refract light in nuanced ways. This predominantly gives the fruit a bluish tinge, but as you angle it, there can also be sparkles of green or red. If you look at the fruit close up, it almost looks pixelated. Researchers calculate that the fruit can reflect up to 30 percent of the light hitting it, similar to a silver mirror.
By relying on structure rather than pigmentation, these fruits also retain their iridescence for a long time — long after the plant has otherwise wilted. Some fruits are known to keep their color for decades after they've been plucked. For instance, a specimen at the Kew Botanical Gardens in London has been glowing since 1974.
In other words, this fruit might just be nature's perfect plant for office decor. It certainly makes for a natural alternative to plastic plants. Though, to be fair, the fruit's unbelievable shine might have people wondering if it's a fake anyway.
Researchers hope that with further study, the glimmering hue of this berry can be mimicked for industrial applications and the invention of new textiles and materials.
"By taking inspiration from nature, it is possible to obtain smart multifunctional materials using sustainable routes with abundant and cheap materials like cellulose," said Dr. Silvia Vignolini, lead author on the paper.
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