A piece today in the New York Times resuscitates the debate about the ethics of eating living things. Why stop at the consumption of animals when other objects, such as plants and fungi, are clearly living beings? According to the “special issue” article, fungi are closer to us on the evolutionary tree than plants, and some plants have a more highly developed nervous system than the brainless jellyfish, creatures we firmly include as part of the animal kingdom. Of course, this argument is a variation on a theme that has seen many iterations, from literary provocations by Jonathan Saffron Foer and David Foster Wallace to the original investigations of the Jainist community. But the parts here that fascinate me the most are descriptions of plant reactions on the cellular level.
Unlike a lowing, running cow, a plant’s reactions to attack are much harder for us to detect. But just like a chicken running around without its head, the body of a corn plant torn from the soil or sliced into pieces struggles to save itself, just as vigorously and just as uselessly, if much less obviously to the human ear and eye.
When a plant is wounded, its body immediately kicks into protection mode. It releases a bouquet of volatile chemicals, which in some cases have been shown to induce neighboring plants to pre-emptively step up their own chemical defenses and in other cases to lure in predators of the beasts that may be causing the damage to the plants. Inside the plant, repair systems are engaged and defenses are mounted, the molecular details of which scientists are still working out, but which involve signaling molecules coursing through the body to rally the cellular troops, even the enlisting of the genome itself, which begins churning out defense-related proteins.
Plants don’t just react to attacks, though. They stand forever at the ready. Witness the endless thorns, stinging hairs and deadly poisons with which they are armed. If all this effort doesn’t look like an organism trying to survive, then I’m not sure what would. Plants are not the inert pantries of sustenance we might wish them to be.
This article from a few years back describes some more about plant reactions and defenses. “Not only can bugs detect the odors plants emit for protection, but many farmers notice when army worms are in their cornfield. They smell very sweet. And plants react to each attack differently, emitting different odors to attract different bugs to help defend them.”