We’ve known for years that plants can see, hear, smell and communicate with chemicals. Now, reported New Scientist, they have been recorded making sounds when stressed.
In a yet-to-be-published study, Itzhak Khait and his team at Tel Aviv University, in Israel, found that tomato and tobacco (烟草) plants can make ultrasonic (超声的) noises. The plants “cry out” due to lack of water, or when their stems (茎) are cut. It’s just too high-pitched (音调高的) for humans to hear.
Microphones placed 10 centimeters away from the plants picked up sounds in the ultrasonic range of 20 to 100 kilohertz (千赫兹). Human hearing usually ranges from 20 hertz to 20 kilohertz. “These findings can change the way we think about the plant kingdom,” they wrote.
On average, “thirsty” tomato plants made 35 sounds an hour, while tobacco plants made 11. When plant stems were cut, tomato plants made an average of 25 sounds in the following hour, and tobacco plants 15. Unstressed plants produced fewer than one sound per hour, on average.
Perhaps most interestingly, different types of stress led to different sounds. The researchers trained a machine-learning model to separate the plants’ sounds from those of the wind, rain and other noises of the greenhouse. In most cases, it correctly identified (辨识) whether the stress was caused by dryness or a cut, based on a sound’s intensity(强度) and frequency. Water-hungry tobacco appears to make louder sounds than cut tobacco, for example. Although Khait and his colleagues only looked at tomato and tobacco plants, they think other plants also make sounds when stressed.
If farmers could hear these sounds, said the team, they could give water to the plants that need it most. As climate change causes more droughts (旱灾), they said this would be important information for farmers. “The sounds that drought-stressed plants make could be used in precision agriculture (精准农业),” said Anne Visscher at the Royal Botanic Gardens, Kew, in the UK.
Khait’s report also suggests that insects and mammals (哺乳动物) can hear the sounds up to 5 meters away and respond. For example, a moth (蛾子) may decide not to lay eggs on a water-stressed plant. Edward Farmer, at the University of Lausanne, Switzerland, is doubtful. He said that the idea of moths listening to plants is “a little too speculative”.
If plants are screaming for fear of their survival, maybe we should be glad we can’t hear them.
4. What did Khait and his team find from their research?
A.Plants made low-pitched sounds when in danger. |
B.Plants made ultrasonic noises to communicate with each other. |
C.Plants picked up a wider range of sounds when stressed. |
D.Plants were able to produce sounds in response to stresses. |
5. How did tomato and tobacco plants react to different stresses according to the text?
A.A plant reacted to different stresses with the same sound. |
B.Cut tomato plants produced more sounds per hour than water-hungry ones. |
C.Cut tobacco plants seemed to make weaker sounds than drought-stressed ones. |
D.Tobacco plants might make louder sounds than tomato plants when short of water. |
6. What’s the main idea of Paragraph 6?
A.Challenges faced by farmers in the future. |
B.The potential applications of the research. |
C.Farmers’ contributions to the research. |
D.What the future agriculture will be like. |
7. The underlined word “speculative” in the second-to-last paragraph has the closest meaning to “______”.
A.practical | B.unsupported |
C.surprising | D.complicated |