Auwe! Nothing! Nada! What's up?

Go to any floral shop and watch the customers. The first thing they (and we) do is attempt to smell the flowers. Disappointment follows when the roses come up empty of aroma.

Scent is the automatic sensory effect we expect from flowers, but alas, science has deprived us of that reward.

Different genes trigger production of volatile compounds, which are molecules in plant cells that generate a flower's scent when they evaporate.

Each flower species has its own unique signature scent, connected to its specific combination of volatile compounds.

To cultivate cut flowers that have consistent quality, long vase life, deep color, are disease-resistant and keep their vigor to grow profusely, some of the scent genes are bred out of the development process. It is an unfortunate byproduct of the molecular structure of flowers.

To shift this tide, geneticists and growers have recently started breeding more perfume back into cut flowers. Flowers and foliage are also beginning to be graded with a scent scale and the type of scent ... sweet, spicy, woody, exotic, etc.

David Clark, an associate professor of environmental horticulture in the University of Florida's Institute of Food and Agricultural Sciences, and his colleagues have mapped 4,000 genes of the petunia. They are working to identify the ones responsible for making the chemicals that produce volatile compounds responsible for scent.

It is foreseeable that one day petunia genes could be used to help return scent to other flowers.

Scent in most flowers is usually produced in the petals. On the surface of the petals is a layer of epidermal cells where various complex types of essential oils are created. The essential oil is stored in special cells that are like hollow containers.

While the flower is closed, the oil remains in storage. As the flower opens, the oil is activated and the intricate chemicals form a vapor that floats around the flower. Flowers with thick, waxy petals continue giving out perfume longer than flowers with thin petals.

In general, the more color (pigmentation) the petals contain, the less essential oil is produced. That's why white flowers tend to be the most aromatic.

In Hawai'i, we smell this blessed reality in coffee blossoms, gardenias, mock orange, pikake, stephanotis, tuberose, white ginger and, of course, our magnificent endemic white hibiscus, koki'o ke'oke'o.

Here in our Island paradise, Mother Nature provides what science took out.

Duane Choy is a volunteer coordinator and heads docent training for the Honolulu botanical gardens. Reach him at hbg@honolulu.gov.

Foster Botanical Garden, 50 N. Vineyard Blvd., is open from 9 a.m. to 4 p.m. daily. For more information about the garden, call 522-7066.