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Hey! You're Hurting My Leaves!

Do plants feel pain when they are attacked? Does your lawn hurt after it is mowed? Scientists are beginning to understand how plants communicate with their leaves and stems.

Plants And Signaling

Scientists have discovered that plants use a form of electrical signaling that spreads throughout the plant when one of its leaves is injured. This signaling is similar to the electric signals that spread through our nerves when humans are injured.

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.

The Discovery

The way these electric signals were discovered is pretty interesting. 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.

So, Do Plants Feel Pain?

In the end, plants do not feel pain. However, 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.

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