Friday, 28 February 2014

The blue that is true?

In fancy flower shop here and in the US, apparently, some intensely blue orchid flowers have been cropping up. I’ve only seen them online. They look distinctly unnatural to me.

In fact, they are white flowers that get their colour from a patented dye used by plant breeders.

File:Orchids, blue.jpg

Blue is a colour that doesn’t occur naturally in orchids, according to an intriguing article about the science of blue flowers.

Fewer than 10 per cent of the 280,000 species of flowering plants produce blue flowers.

Why, you ask?  There is no true blue pigment in plants, so plants don’t have a direct way of making a blue colour. Blue is even rarer in foliage than it is in flowers.

This floral con trick is done using common plant pigments called anthocyanins, more commonly associated with antioxidants.

It’s done with modifications involving pH shifts and mixing of pigments, molecules and ions.

Natural blue flowers include, delphinums, plumbago, bluebells, and some agapanthus, hydrangeas, dayflowers, morning glories and cornflowers.

Surprisingly, they are still attractive to pollinators. Insects and birds detect blue as a wavelength.

Blue is much sought-after, specifically because it’s rare. Imagine how much fuss there'd be over a true blue rose, for example.

Genuine horticulturalists are trying to achieve truly blue flowers shun the dye approach and are turning to biotechnology. Chemists have employed delphinidin and produced a purple rose, but that’s it. No joy with carnations, either. Blue is elusive.

 File:Green Carnation.jpg

PS: We had a Green Carnation Ball at Oxford. We tried to gas them using ammonium and I nearly passed out because I was standing too near to the fume hood. Then we tried sticking white carnation in green ink. Much staining ensued. In the end, we made them out of green tissue paper. Why green carnations? It’s all to do with fin de siècle decadence, apparently. Read it here.

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