Plants may lack brains, but they have a nervous system, of sorts. And now, plant biologists have discovered that when a leaf gets eaten, it warns other leaves by using some of the same signals as animals. The new work is starting to unravel a long-standing mystery about how different parts of a plant communicate with one another.

Animal nerve cells talk to each other with the aid of an amino acid called glutamate, which—after being released by an excited nerve cell—helps set off a wave of calcium ions in adjacent cells. The wave travels down the next nerve cell, which relays a signal to the next one in line, enabling long-distance communication.

Source: Plants communicate distress using their own kind of nervous system