Nghe TOEFL

🎧 Bản ghi âm

Listen to part of a lecture in an environmental science class. Professor: Today we’re going to discuss a surprising factor that influences plant growth: sound. You might think that plants only respond to light, water, and nutrients, but recent studies have shown that certain plants can detect vibrations, such as the sound of caterpillars chewing on leaves. In a study, researchers placed caterpillars on some plants and played recordings of chewing sounds near other plants that had no caterpillars. Both groups of plants produced chemical defenses. However, plants that were exposed only to the recorded sounds—without any actual caterpillars—reacted more quickly and with stronger defenses. This suggests that plants can distinguish between meaningful sounds and background noise. Interestingly, the plants did not respond to vibrations from wind or other harmless sounds. So, while plants don't have ears, they may use mechanical vibrations to sense threats. This research could lead to new ways of protecting crops without pesticides. Now, what is the main point of this lecture?