Plants can talk, apparently

Davis, CA – Prince Charles famously talks to them, but nobody knew they talked to each other – until now.

Plants engage in self-recognition and can communicate danger to  genetically identical cuttings planted nearby, according to professor Richard Karban of the University of California.

Karban and fellow scientist Kaori Shiojiri of the Center for Ecological Research, Kyoto University, Japan, found that sagebrush communicated and cooperated with its cuttings to avoid being eaten by grasshoppers.

The scientists made cuttings from 30 sagebrush plants at the UC Sagehen Creek Natural Reserve and grew the cuttings in plastic pots. They then placed the pots either near the parent plant or near a control group in the field.

Karban and Shiojiri examined the relationships between the volatile profiles of clipped plants and herbivore damage. They found that plants within 60 centimeters of an experimentally clipped neighbor in the field experienced less leaf damage over the season, compared with plants near an unclipped neighbor. Plants with root contact between neighbors, but not air contact, failed to show this response.

The ecologists wrote that “naturally occurring herbivores caused similar responses as experimental clipping with scissors and active cues were released for up to three days following clipping. Choice and no-choice experiments indicated that herbivores responded to changes in plant characteristics and were not being repelled directly by airborne cues released by clipped individuals.”

Although the research is in its early stages, the scientists suspect that the plants warn their own kind of impending danger by emitting volatile cues. This may involve secreting chemicals that deter herbivores or make the plant less profitable for herbivores to eat. It means that plants are “capable of more sophisticated behavior than we imagined,” said Karban, who researches the interactions between herbivores and their host plants.
“Plants are capable of responding to complex cues that involve multiple stimuli,” Karban said. “Plants not only respond to reliable cues in their environments but also produce cues that communicate with other plants and with other organisms, such as pollinators, seed dispersers, herbivores and enemies of those herbivores.”

The research is published in the current edition of Ecology Letters.