Wednesday, March 4, 2009

Flowers losing their scent

By Tracy Anderson

In today's hectic world, do you ever find time to stop and smell the roses? If you do, don't be surprised if you smell nothing. Researchers say the scent of many flowers including roses are vanishing and they're finding ways to bring it back.

This depressing news comes from Natalia Dudareva, assistant professor of reproductive biology in the Department of Horticulture and Landscape Architecture at Purdue University in Indiana.

The Russian flower researcher is upset that many flowers don't smell the same anymore - and many have no scent at all compared to their ancestors.

The reason: modern plant breeding methods used by the $30-billion ornamental flower industry have diminished the scent of popular flowers.

Alan Blowers, flower biotechnology head for Ball Helix, a biotech company in West Chicago, Illinois, said color takes the No. 1 priority when it comes to breeding. As growers work to improve the life of cut flowers - their shapes and sizes - this has somehow affected the way the latter smell.

"Selective breeding has reduced flower scent to almost nothing. Flowers are bred for color, size and shelf life without any attention to scent. Floral scent disappeared, and nobody knows why," Dudareva said.

Now she and her colleagues are finding ways to bring back the old scents and perhaps create new ones. Her research will benefit not only horticulturists but agriculturists as well. The future of three-fourths of all crops depends on insect pollinators who are attracted to the scent of flowers. Without these insects, these crops can't multiply and will die.

The scents are made by volatile compounds in plants and have a number of important uses. They not only make flowers smell nice but attract pollinators and repel pests. These volatile compounds are also used to warn other plants.

"Plants use floral scents to attract pollinators or to repel harmful insects. Floral scents begin as oils that are produced by the petals in most plants. Because these oils evaporate easily in warm weather, scientists call them volatile compounds. The aroma of a flower may contain as few as seven to ten different oils, as in snapdragon or petunia, or as many as 100 different chemicals, as is the case with orchids," explained the editors of ScienceDaily.Com.

"There are known examples of plants that have been infected with a virus and have released a volatile compound that signals other plants to set up defenses against the virus," Dudareva added.

By understanding how volatile compounds are produced and what genes are involved, Dudareva hopes to produce more sweet-smelling flowers and even control the time they release their scent.

"The floral industry is interested in creating flowers that are fragrant in the evening, when people come home from work. Petunia is one flower that releases its scent in the evening, so we should be able to do this. But before we can make flowers more fragrant in the evening, we need to increase the scent overall," she concluded. - 15437

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