Plants that can smell
ASHINGTON (AP) - The parasitic dodder plant doesn't have a nose, but it knows how to sniff out its prey. The dodder attacks such plants as tomatoes, carrots, onions, citrus trees, cranberries, alfalfa and even flowers, and is a problem for farmers. So discovering how it finds its prey might help lead to a way to block the weed, or for crops to defend themselves, say researchers at Pennsylvania State University. Many thought it simply grew in a random direction, with discovery of a plant to attack being a chance encounter. But the researchers found that if they placed tomato plants near a germinating dodder, the parasite headed for the tomato 80 percent of the time. And when they put scent chemicals from a tomato on rubber, 73 percent of the dodder seedlings headed that way. Co-author Mark C. Mescher added, "One of the interesting things we found was that the plants make choices." When they gave the dodder seedlings a choice between a tomato plant and a wheat plant, they