Despite the growing evidence that plants are capable of communication, many plant scientists still question whether this cross talk is biologically meaningful. “Interplant communication through volatiles works well in the lab, but nobody’s convincingly shown it works in the field,” said Farmer. Even though he was one of the first to publish evidence that plants are capable of exchanging information, he calls himself a “skeptic” — he thinks there’s not yet enough evidence that this actually plays a significant role in plant lives. “But I wouldn’t want to stop people working on it,” he added. “I think it’s promising and exciting.”
For both Karban and Heil, the outstanding question is evolutionary: Why should one plant waste energy clueing in its competitors about a danger? They argue that plant communication is a misnomer; it really might just be plant eavesdropping. Rather than using the vascular system to send messages across meters-long distances, maybe plants release volatile chemicals as a faster, smarter way to communicate with themselves — Heil calls it asoliloquy.
Other plants can then monitor these puffs of airborne data. Bolstering this theory, most of these chemical signals seem to travel no more than 50 to 100 centimeters, at which range a plant would mostly be signaling itself.Most Popular
The possibility that plants routinely share information isn’t just intriguing botany; it could be exploited to improve crop resistance to pests. A 2011 report found that commercial corn hybrids seem to have lost the wild maize plant’s ability to release chemicals that attract parasitic wasps that kill stem borer moths. If these defensive traits could be bred back into crops, they could reduce the need for pesticides. Another possibility might be to grow plants with particularly sensitive or potent defensive responses alongside field crops. Like a canary in a coal mine, these sentinels would be the first to detect and react to danger, alerting neighboring crops.
Whether or not such practical applications come to pass, the science of plant talk is challenging long-held definitions of communication and behavior as the sole province of animals. Each discovery erodes what we thought we knew about what plants do and what they can do. To learn what else they’re capable of, we have to stop anthropomorphizing plants, said Baldwin, who is now at the Max Planck Institute in Germany, and try instead to think like them, to phytomorphize ourselves. Imagining what it’s like to be a plant, he said, will be the way to understand how and why they communicate — and make their secret lives a mystery no longer.