植物在受到压力时发出的声音太高，人的耳朵听不到

Some plants emit “ultrasonic clicks” inaudible to the human ear when under life-threatening stress, a new study has found. Recordings reveal each sound contains information about a plant’s current state of being.

一项新的研究发现，一些植物在受到威胁生命的压力时，会发出人耳听不到的“超声波滴答声”。录音显示，每一种声音都包含着植物当前状态的信息。

“These findings can alter the way we think about the Plant Kingdom, which has been considered to be almost silent until now,” write the study authors in a paper available to read on preprint server bioRxiv. The findings have not been published in a journal nor have they been certified by peer review, but the researchers say that their findings add to the scientific understanding of plant evolution and ecology around the world.

“这些发现可能会改变我们对植物王国的看法，在此之前，植物王国一直被认为几乎是沉默的，”该研究的作者在一篇可以在bioRxiv预印本服务器上阅读的论文中写道。这些发现既没有发表在期刊上，也没有得到同行评审的认证，但研究人员表示，他们的发现有助于科学地理解世界各地的植物进化和生态。

Previous studies have found that stress caused by changes in temperatures and light, as well as “herbivore attack,” can alter a plant’s phenotype, resulting in changes in color, smell, and shape. Stressed plants have also been found to give off volatile organic compounds. To examine whether plants make audible sounds as well, researchers at Tel Aviv University recorded tomato and tobacco plants that were deprived of water, having their stems cut, or were otherwise comfortable. Microphones focused on an ultrasonic sound range between 20 and 150 kHz.

以前的研究发现，温度和光线的变化以及“食草动物攻击”造成的压力会改变植物的表型，导致颜色、气味和形状的变化。压力大的植物也会释放出挥发性有机化合物。为了研究植物是否也会发出可听见的声音，特拉维夫大学的研究人员记录了番茄和烟草植物在缺水、茎被切断或其他舒适环境下的情况。麦克风聚焦在20至150千赫的超声波范围内。

Stressed plants were found to emit significantly more sounds than plants from the comfortable control group. Not only were they noisier, but the researchers claim that they gave off different sounds depending on what was happening; sounds that carried information about the physiological state of the plant. A specially designed machine learning model was reportedly capable of distinguishing between plant sounds and general background noise, going so far as to identify whether a plant was water-deprived or being cut.

研究发现，压力大的植物发出的声音明显比舒适对照组的植物更多。它们不仅噪音更大，而且研究人员声称，它们发出的声音也会根据所发生的事情而有所不同;声音传递着植物生理状态的信息。据报道，一种特别设计的机器学习模型能够区分植物的声音和一般的背景噪音，甚至能够识别植物是否缺水或被砍伐。