The science of the Edelweiss

The Sound of Music always brings a tear to mah eye. And now it’ll have new meaning thanks to the sterling work of Jean Pol “Pot” Vigneron and his buddies at the Facultes Universitaires Notre-Dame de la Paix in Belgium.

Pol Pot has been a-caressin’ and a-cuddlin’ one of the movie’s stars: the Alpine flower Edelweiss, and has discovered that the white hairs covering its leaves are actually photonic structures tuned to ultraviolet wavelengths. So Edelwiess turns out to be one of only a handful of plants that can actually grow photonic structures.

In the Alpine meadows where Edelweiss grows, UV levels are much higher than at lower altitudes and would ordinarilly damage plant cells. But the hairs prevent UV light from reaching the leaves while allowing other colours to pass unhindered. Pol Pot says the hairs are hollow tubs with ridges running along their length that trap light at UV wavelengths.

One outstanding mystery is what happens to the UV light once it becomes trapped in the filament. Pol Pot and his team have been a-contemplatin and a-meditatin on this for a while now and speculate that the tubes may be filled with water which absorbs UV light.

The hairs may even turn out to be be useful. Most UV sun screens rely on nanometre-sized particles of titanium oxide which can be difficult to handle and may not be usable for certain applications such as food packaging. Now we have an alternative: the hairs from the Alpine flower Edelweiss

Ain’t thatta bee-yoo-tiful piece of science?

Altogether now…

Edelweiss, Edelweiss
Every morning you greet me
Small and white,
clean and bright
You look happy to meet me.
Blossom of snow
may you bloom and grow,
Bloom and grow forever.
Edelweiss, Edelweiss
Bless my homeland forever.


Ref: : Optical Structure and Function of the White Filamentary Hair covering the
Edelweiss Bracts

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