https://science.howstuffworks.com/life/botany/plants-feel-pain.htm According to researchers at the Institute for Applied Physics at the University of Bonn in Germany, plants release gases that are the equivalent of crying out in pain. Using a laser-powered microphone, researchers have picked up sound waves produced by plants releasing gases when cut or injured. Although not audible to the human ear, the secret voices of plants have revealed that cucumbers scream when they are sick, and flowers whine when their leaves are cut [source: Deutsche Welle]. From now on, I'm going to feel badly eating a salad. Please Register or Log in to view the hidden image!