Why Your Roses Smell Nice

Hint — it’s mostly coincidence

By Maxine Singer

The appeal of many floral scents to humans is a fortunate byproduct: We were not even around when they appeared. And, for all the effort, commercial perfumes rarely smell like flowers. Expensive, fancy bottles labeled jasmine or gardenia may smell wonderful but they are sad substitutes for the real thing.

One reason is that flowers generally produce very large mixtures of different volatile molecules, as many as a thousand. Some of these fall into related chemical groups and although they differ very slightly in chemical structure, they can produce very different smells. In closely related flowers, the volatile molecules can vary both in relative amounts (reflecting differential regulation of the genes and gene products needed) and in their chemical structures (reflecting the activity of genes evolved to produce the enzymes needed for synthesis). It’s not easy to figure out which components of a mixture are important for attracting insects or birds or for achieving a perfume attractive to people. It is especially challenging because our own sense of smell depends on a complex set of nerve cells and often differs from one person to another. The manufacture of the odors depends on a plant’s genes, and the ability of animals, including ourselves, to smell those odors depends on the animals’ genes.

As with colors, the chemistry of volatile compounds that affect smell depends on the presence of genes that encode protein enzymes. These enzymes act in sequence to produce the complex scented molecules from precursor molecules whose presence depends on still other genes and enzymes. The relative amounts of the different molecules depend in turn on other genes that code for RNAs and proteins important for the regulation and modulation of the genes required to manufacture the scents.

When we smell a rose, we are picking up a mixture of several hundred different molecules. Each one of these is the result of a series of genes and the enzymes they code for that enable particular chemical reactions in the rose petals. Many of the volatile molecules are made…

Related posts:

Driving in along that coastal plain, bleached stubble flowing to the cliff tops on the left, up over the diminutive hillocks to the right, a feeling of strangeness and unreality began to set in. Dry…

Jasmine is the most popular JS library for unit testing web apps. In this tutorial, designed for beginners, we’ll present you with a quick and complete guide to testing with Jasmine. You’ll get…

There was a recent study by a student at California State University San Marcos linking “The Veggie Tales” Christian animated series and movies to racism. The claim is that the characters portrayed…