Listening to Plants
Some people have the green thumb in their family. Others may complain that they fail with plants because plants don't tell them when they need care. Of course, most people can do well with family pets, who are enthusiastic about letting their needs be known.
Now scientists have learned that plants do indeed cry out when they need attention. We just haven't heard them because the sounds made by a thirsty plant are about five times higher-pitched than we can hear. But scientists with tiny specialized microphones have heard corn plants calling for water. During their study, researchers learned that plants make a great deal of noise. Corn leaves and stalks make noises as they slide against each other during growth. We have all heard the sound of plant leaves rattling in the wind. Corn stalks also make noise as they bend in the wind.
However, another sound was heard when the corn didn't have enough water. It was a high-pitched popping noise. Plants have water tubes in them that carry water and nutrients up from the roots to the leaves. Water flows up these tubes under tension. When there is not enough water, the tension becomes too great and the tubes fracture. The popping is the sound of those tubes fracturing. The result of fractured tubes is a wilted plant. When water is restored, the tubes refill, the popping noises stop, and the plant again looks healthy.
The purpose of this research was to learn when to water crops and how much water they need. Now that we have learned how plants communicate, crops can tell farmers when to water!