【英语时差8,16】嘿！你伤到我的树叶了！（在线收听）

Hey! You’re Hurting My Leaves! D:Yael,the last time I was mown the lawn,I couldn't help thinking,it's lucky these grass plant don't feel pain Y:Ture,Don.But did you know that scientists have discovered that plants use a form of electrical signaling that spreads throughout the plant when one of its leaves is injured. D:Like the electric signals that spread through our nerves when we are injured? Y:The electric signals in plants, called “system potentials”, are not exactly like the electric “action potentials” in the nervous systems of animals. But they do have certain similarities. Both kinds of electric signals travel very quickly from the site of the wound to distant parts of the organism. D:Cool. Y:The way these electric signals were discovered is pretty cool,too. A team of German scientists carefully inserted super thin, hair like electrodes through open stomata on the leaves. Stomata are tiny pores, found on the undersides of leaves, that open and close to control evaporation and gas exchange for the plant. The tiny electrodes could then record activity from cells inside the leaf.Using these sensitive electrodes, the scientists were able to record changes in voltage as the electric signals spread from leaf to leaf across the entire plant. The system potentials in plants move much more slowly than the electric signals that run through our neurons, spreading at rates between two to four inches per minute. D:So,can my grass feel pain? Y:No.Plants don't have brains or feelings the way animals do.But it is important for plants to detect damage from herbivores, insects or even lawnmowers. Electrical signaling is one way plants know there is damage and it’s time to activate defense mechanisms or begin re growth in damaged areas.