By CAROL KAESUK YOON
Published: June 10, 2008
From its diminutive lavender flowers to its straggly windblown stalks, there is nothing about the beach weed known as the Great Lakes sea rocket to suggest that it might be any sort of a botanical wonder.
A plant organism could ramp up nasty behavior against unrelated individuals with which it is most sensible to be in claws- or perhaps thorns-bared competition.
“I’m just amazed at what we’ve found,” said Susan A. Dudley, an evolutionary plant ecologist at McMaster University in Hamilton, Ontario, who carried out the study with a graduate student, Amanda L. File.
“Plants,” Dr. Dudley said, “have a secret social life.”
Since the research on sea rockets was published in August in Biology Letters, a journal of the United Kingdom’s national academy of science, Dr. Dudley and colleagues have found evidence that three other plant species can also recognize relatives.
The studies are part of an emerging picture of life among plants, one in which these organisms, long viewed as so much immobile, passive greenery, can be seen to sense all sorts of things about the plants around them and use that information to interact with them.
Plants’ social life may have remained mysterious for so long because, as researchers have seen in studies of species like sagebrush, strawberries and thornapples, the ways plants sense can be quite different from the ways in which animals do.
Some plants, for example, have been shown to sense potentially competing neighboring plants by subtle changes in light. That is because plants absorb and reflect particular wavelengths of sunlight, creating signature shifts that other plants can detect.
Scientists also find plants exhibiting ways to gather information on other plants from chemicals released into the soil and air. A parasitic weed, dodder, has been found to be particularly keen at sensing such chemicals.
Dodder is unable to grow its own roots or make its own sugars using photosynthesis, the process used by nearly all other plants. As a result, scientists knew that after sprouting from seed, the plant would fairly quickly need to begin growing on and into another plant to extract the nutrients needed to survive.
But even the scientists studying the plant were surprised at the speed and precision with which a dodder seedling could sense and hunt its victim. In time-lapse movies, scientists saw dodder sprouts moving in a circular fashion, in what they discovered was a sampling of the airborne chemicals released by nearby plants, a bit like a dog sniffing the air around a dinner buffet.
Then, using just the hint of the smells and without having touched another plant, the dodder grew toward its preferred victim. That is, the dodder reliably sensed and attacked the species of plant, from among the choices nearby, on which it would grow best.
“When you see the movies, you very much have this impression of it being like behavior, animal behavior,” said Dr. Consuelo M. De Moraes, a chemical ecologist at Pennsylvania State University who was on the team studying the plant. “It’s like a little worm moving toward this other plant.”
If you have new of contrasting information or opinion about any of this, please send me an email: Don White regarding “Plants Are Attracted To Other Plants”