MICHELE NORRIS, host:
This is ALL THINGS CONSIDERED from NPR News. I'm Michele Norris.
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And I'm Melissa Block.
This next story is about a plant that smells. No, not a flower with a pleasing fragrance. This plant is a parasitic vine that has a remarkable ability to sniff out its victim.
NPR's David Malakoff reports.
DAVID MALAKOFF: The vine is called dodder. Among farmers it has a nasty reputation for damaging crops. In fact, they've put dodder on a kind of a ten most wanted list of weeds. And like many dangerous characters, dodder has some colorful aliases - Strangle Weed, Devil Guts, Witch's Shoelaces.
Professor COLIN PURRINGTON (Swarthmore College): Dodder is probably one of the creepiest plants I know of.
MALAKOFF: Colin Purrington is a dodder expert at Swarthmore College in Pennsylvania. He says the vine starts out as just a tiny tendril. No roots, no leaves, and the seedling has just a week or so to find a host plant it can wrap around. Then like a vampire, the dodder sinks some fleshy fangs into its victim and starts drinking.
Professor PURRINGTON: It's a horrible existence for the host plant. If plants could scream, they'd have the loudest screams when they had dodder attached.
MALAKOFF: Exactly how dodder hones in on its victims has been a bit of a mystery. The vine might be attracted to water vapor or maybe the light that reflects off a potential host. But three researchers at Pennsylvania State University wondered if dodder was following the scent of its victim. And as it turns out, they were right.
Consuelo De Moraes was on the team. She says when they wafted, say, eau de tomato in the direction of a dodder seedling, the tendril almost always began to creep toward the smell.
Ms. CONSUELO DE MORAES (Pennsylvania State University): It's really amazing to watch this plant having this almost animal-like behavior. It's really very sophisticated and surprising.
MALAKOFF: The study also showed that dodder likes some plants more than others. Give it a choice of tomato or wheat and the vine usually goes for the tomato. That may be because the wheat gives off a chemical that repels the vine. Mark Mescher, another Penn State scientist who worked on the study, says that could be good news for farmers.
Mr. MARK MESCHER (Pennsylvania State University): The fact that there are these repellant compounds suggest that you might be able to create a repellant or a deterrent effect that would allow you to protect an agricultural crop against infestation.
MALAKOFF: Details of the dodder's olfactory talent appear in the current issue of the journal Science.
David Malakoff, NPR News.