题型：语法填空（语篇） 题类：模拟题 难易度：困难
上海市奉贤区2020届高三下学期英语二模考试卷
Plants Scream in the Face of Stress
For the first time, researchers appear to have evidence that like animals, those plants deprived of water or (force) to endure bodily harm can let out their pain. The study, has yet to be published in a scientific Journal, adds another dimension to scientists (grow) understanding of how plants detect and interact with their surroundings.
In recent years, it has become very clear that plants are more sensitive than researchers (think). They respond when touched by insects and turn toward sources of light. "Plants are not just robotic stimulus-response devices," said Frantisek Baluska of the University of Bonn in Germany. "They're living organisms which have their own problems."
Actually making their suffering hearable, however, is another matter entirely. (test) that possibility, a team led by Itzhak Khait, a plant scientist at Tel Aviv University in Israel, placed microphones capable of detecting ultrasonic frequencies (超声波频率) four inches from tomato and tobacco plants. The researcher then either stopped watering them or cut their stems.
Measuring in the range of 20 to 150 kilohertz (千赫), the researchers found that even happy, healthy plants made the occasional noise. But when cut, tobacco plants emitted average of 15 sounds within an hour of being cut, tomato plants produced 25 sounds.
researchers aren't yet sure how plants produce these sounds, Khait and his colleagues proposed one possibility in their paper as water travels through the plants' tubes, air bubbles will form and explode, producing small vibrations.
All this "screaming" caused by stress wasn't in a range detectable by human ears. But organisms that can hear ultrasonic frequencies--like mice, bats or perhaps other plants-- possibly hear the plants cries from as far away as 15 feet.
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