Human beings, like all members of the animal kingdom, are capable of awareness of their environment due to the presence of sensory organs, a nervous system, and of course, a brain. In the absence of these key attributes, it seems unlikely that a living organism would be aware of its environment on any level (or any at all) that would be comparable to humans and the animal kingdom.
This fundamental observation never kept polygraph expert Cleve Backster from delving into the secretive realm of plant consciousness, however. Beginning in 1966, the CIA Interrogation Specialist had been conducting experiments with plants hooked to polygraph equipment, when he first noticed that in some instances the plants would "react" to various stimuli in ways that suggested some level of awareness pertaining to their environment. Incredibly, Backster claimed to observe how some plants would cause polygraph readings similar to a person in distress when burned or harmed otherwise. On some occasions, the same effect could be registered as a result of Backster merely thinking about harming the plant in question.
And of course, as a result of his "studies," Backster was labeled a crackpot by the skeptic community for ever suggesting an organism with no central nervous system could have any level of awareness of this sort. However, recent studies regarding what could be likened to "communication" between plants has now shown that plants might have been keeping a few secrets from us after all... and that perhaps a few of Cleve Backster's more unorthodox claims could have some justification, after all.
For the first time, scientists at Exeter University have now captured on film the process by which plants alert each other to possible dangers. When a plant is under attack, it releases a gas that warns neighboring plants to protect themselves. It was already known that plants will secret a quick-acting toxin to help ward off herbivores seeking to consume them. Now, scientists at Exeter University who made the new discovery have likened their observations to “listening in on a conversation.” Upon release of the “warning” gas by a plant that is under attack, other plants nearby begin to react in a way that shows they are preparing for an “attack,” after coming into contact with the gases released by the initial plant. Following this remarkable study, scientists are now wondering if there could literally be, “a chatter between plants all around us.”
While this may not lend justification to the idea of plant awareness or consciousness, it certainly does illuminate some unique possibilities regarding Cleve Backster's original research from the late 1960s. Among Backster's claims, in addition to observing alleged reactions of plants using polygraph equipment, had been a few instances where a reaction could be garnered when another plant in the room had been "attacked." That is, while one plant may have had, for instance, a flame held to it's leaves, a different plant nearby that was hooked to a polygraph machine would register some form of response, which seemed to coincide with this "attack" occurring elsewhere. Knowing what we do now, especially with regard to how plants can secrete enzymes not only to protect themselves, but also to release gases that "communicate" dangers occurring nearby, does it illustrate that maybe certain aspects of Backster's observations were correct after all, but perhaps interpreted inaccurately at times?
For more on Cleve Backster and his research, here is a classic video narrated by Leonard Nemoy that appeared on In Search Of... as well as this ever-enjoyable entry from over at the Skeptic's Dictionary, which is almost laughable in its overt condescension.