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Roses immortal

February 14, 2011

How to make love last? US horticulturists have one answer: splice celery and rose DNA to help roses fight disease. They hope to give the symbol of love some extra staying power.

https://p.dw.com/p/10Gol
Two roses
Researchers hope to create longer lasting rosesImage: AP

American researchers say they have set out to extend the "vase life" of Valentine's Day's most iconic gift. By inserting genes from celery into roses, the scientists hope to strengthen the flower's immune system and help it fend off disease.

The rose's biggest worry after being harvested is a fungal disease called petal blight. When the fungus known as Botrytis latches on to a rose, it can lead the plant's petals to look mushy and gray.

To stop the fungus, horticultural researchers from North Carolina State University in the US inserted a gene called mannitol dehydrogenase contained in celery into roses. Mannitol dehydrogenase helps fight against a sugar alcohol called mannitol, which is produced by fungal pathogens and leads flowers to wilt.

"This gene is found naturally in many plants, but it's uncertain whether the rose already has it," Williamson said in a press release. "If it does, it doesn't produce enough enzyme to help the plant fight against petal blight."

Grapes infected with the Botrytis fungus
The Botrytis fungus infects many plants, creating a wilted, gray appearanceImage: picture alliance/dpa

Four-week roses

Combining celery and rose DNA is just one approach the scientists are taking to building a better rose. They've also examined which sugars should be mixed with the water given to roses post-harvest and studied variances in water quality around the country to see where roses live the longest.

Their ultimate goal is to produce a rose that can survive for three to four weeks after being harvested.

But lovers of the traditional, all-natural flowers have nothing to fear, according to the researchers. The roses in their test beds look and smell every bit like the run-of-the-mill versions of the plant that haven't been genetically modified.

Top seller

The research could have an impact on the rosy prospects of the floral industry. In 2010, Germans spent a total of 3 billion euros ($4 billion) on cut flowers.

Although Valentine's Day is a relatively new concept in Germany, flower sales in the week leading up to February 14 last year totalled between 110 and 120 million euros. And that was a bad year, said one industry representative to the dpa news agency, adding that icy weather on February 14 and distractions from Carnival hindered sales.

Among the flowers sold, roses remain king. Estimates put the number of roses imported into the country at over one billion in 2010.

Author: Greg Wiser
Editor: Stuart Tiffen