JERUSALEM – An Israeli scientist has found a way to defer the droop in daisies and firm up flaccid freesia. He feeds them Viagra.

Rapidly wilting blooms are the bane of the floral industry, which often has a short window of time before harvested flowers become unusable.

Ya'acov Leshem, a professor of plant physiology at the Life Sciences Faculty of Bar Ilan University, and his colleague Ron Wills, of Australia's University of Newcastle, have been researching the loss of firmness, or "plant plasticity problem" – a phenomenon similar to impotency in humans.

"Aging in plants and in men is connected to the decrease in normal production of a molecule called cyclic GMP (guanosyl monophosphate)," Leshem explained. "This leads to a decrease in the plasticity of the spongy tissue in the male penis and in plants. This is part and parcel of the normal biological process."

Leshem and Willis had received a patent for their work on extending the shelf life of fruits and vegetables using nitric oxide. When Leshem read the literature on Viagra, also known by its chemical name, sildenafil citrate, he realized its effect might be similar to that of nitric oxide.

Leshem discovered that, like nitric oxide, Viagra inhibits the enzyme that breaks down the cyclic GMP, and that it actually keeps flowers erect and alive for up to seven days beyond their normal life span.

When he began working on the experiment, he approached Viagra manufacturer Pfizer, but they were not particularly interested in providing him with samples. "They gave me a rather evasive answer," he said.

Undeterred, Leshem found an Israeli doctor who was intrigued and who provided him with a prescription for Viagra. Then he set to work testing cut flowers, one of Israel's biggest exports, by dissolving "a much smaller [amount] than humans take" of the pill, and adding it to the plants' water.

It also has an energizing effect on fruits and vegetables, yet Leshem is not suggesting it be added to anything edible. "We don't know the effect it might have," he said.

"Compounds like the ones mentioned in this study are found frequently by chance, but the real test will come when they are compared to the industry standards currently employed in the trade today," said Dennis Stimart, professor of horticulture at the University of Wisconsin.

"If Viagra is keeping flowers alive for three to four weeks post-harvest compared to controls which are lasting 10 to 12 days, then we may have something to pay more attention about."

Leshem will be presenting his findings on Viagra, together with his work on nitric oxide, at the International Conference on Fresh-Cut Produce in England in September.

Pfizer declined to comment on Leshem's research.