Plants Make Sounds When Stressed

植物壓力大也會(huì)“說話”

Take care of your plants！ They may “scream” if you treat them badly. Although this is an exaggeration， plants can make sounds when they are stressed， according to a paper published in Cell.

“Plants interact with insects and other animals all the time， and many of these organisms use sound for communication， so it would be very suboptimal for plants not to use sound at all，” Lilach Hadany， co-author of the study， told Science Focus.

With this in mind， the research team started by recording plants sounds. They placed tobacco and tomato plants in soundproof boxes to shut off the noise in the environment. Several ultrasonic microphones were then put near the plants， which can record at frequencies between 20 and 250 kilohertz. The maximum frequency that a human adults ear can hear is about 16 kilohertz.

愛護(hù)你的植物吧！如果不好好侍弄你的植物，它們可能會(huì)“尖叫”。雖然“尖叫”是一種夸張的說法，但發(fā)表在《細(xì)胞》雜志上的一篇論文指出，植物在受到壓力時(shí)也會(huì)發(fā)出聲音。

論文合著者Lilach Hadany在接受《科學(xué)焦點(diǎn)》雜志采訪時(shí)表示：“植物一直在與昆蟲和其他動(dòng)物互動(dòng)，其中許多生物之間都用聲音交流，所以對(duì)植物來說，完全不發(fā)出聲音是非常不利于交流的。”

考慮到植物會(huì)用聲音交流，研究團(tuán)隊(duì)開始記錄植物的聲音。研究人員將煙草和番茄植株置于隔音箱中，隔絕環(huán)境中的噪聲，然后將幾個(gè)超聲波麥克風(fēng)放在植物附近。這些麥克風(fēng)可以捕捉頻率為20千赫至250千赫的超聲波，而成年人能聽到的最高頻率約為16千赫。

There were three groups of plants： One group wasnt watered for five days， another group had the stems cut off and the last group was untouched. The microphones caught sounds at a frequency of 40 to 80 kilohertz from the first two groups.

The sound， which was similar to the noise of popcorn popping when “translated” into a frequency humans can hear， grew louder and louder during the five days of water stress. They then began to decline as the plants dried out. A stressed plant produced the popping sound around 30 to 50 times per hour， while the untouched group only produced around once per hour， according to the study.

The researchers havent yet discovered how the sounds are made. One theory is that they could be made during cavitation， which is a process of an air bubble in the plant collapsing under some kind of pressure.

After the experiment， the team gathered the data on stressed plants and then made machine-learning software that could tell how plants “feel”. It could differentiate between unstressed plants， thirsty plants and cut plants， which can be useful for farmers in monitoring the conditions of their crops.

研究人員放置了三組植物：一組植物五天沒有澆水，另一組植物的莖被剪掉，最后一組植物則保持了原狀。據(jù)前兩組的麥克風(fēng)錄音顯示，這些植物發(fā)出了頻率在40千赫至80千赫的聲音。

將植物發(fā)出的聲音“轉(zhuǎn)譯”為人類能聽到的頻率，會(huì)聽到一種類似于爆米花爆裂的聲音，而在缺水的五天里，爆裂聲變得越來越大。然后，隨著植物干枯，聲音開始變小。研究表明，一株受到壓力的植物每小時(shí)發(fā)出大約30至50次爆裂聲，而未受到壓力的植物每小時(shí)只發(fā)出約一次聲音。

研究人員尚未發(fā)現(xiàn)這些聲音是如何產(chǎn)生的。有一種理論認(rèn)為，聲音可能是因發(fā)生氣穴現(xiàn)象而產(chǎn)生，該現(xiàn)象是指植物中的氣泡在某種壓力下破裂的過程。

實(shí)驗(yàn)結(jié)束后，研究團(tuán)隊(duì)收集了受到壓力的植物的數(shù)據(jù)，而后開發(fā)了機(jī)器算法軟件，用以識(shí)別植物的“感覺”。該軟件可以區(qū)分未受到壓力的植物、缺水的植物和受損的植物，因此對(duì)農(nóng)戶監(jiān)測(cè)作物的生長(zhǎng)狀況大有助益。

Word Bank

soundproof /'sa?ndpru?f/ adj. 隔音的

differentiate /'d?f?'ren?ie?t/ v. 區(qū)分；辨別

Its difficult to differentiate between the two varieties.