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    2. VOA英語學習網 > 科學美國人 > 2019年科學美國人 > 科學美國人60秒科學系列 >
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      科學美國人60秒: 小麥“打噴嚏”并傳播疾病

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      Wheat Plants "Sneeze" and Spread Disease

      小麥“打噴嚏”并傳播疾病

      Humans can spread disease by sneezing. But less well known is the wheat plant's ability to do something strangely similar, from its leaves. "It's basically analogous to a human sneeze, in terms of, you have a very fast and sudden expulsion of droplets that contain the disease or pathogen inside of it, and they get thrown away from the surface."

      人類可以通過打噴嚏傳播疾病。但鮮為人知的是,小麥也能從它的葉子中做一些奇怪的類似的事情。“從根本上說,這就像人類打噴嚏一樣,飛沫會迅速、突然地排出含有疾病或病原體的飛沫,然后飛沫就會從表面被拋出。”

      Jonathan Boreyko, a mechanical engineer at Virginia Tech. He and his team were studying the ability of wheat plants to expel spores of a common pathogen, the wheat rust fungus, from their leaves via this unusual mechanism. So they inoculated wheat plants with the disease, created dew on the plants' leaves, and then studied the ensuing action with high speed microscopy.

      Jonathan Boreyko是弗吉尼亞理工大學的機械工程師,他和他的團隊正在研究小麥植株通過這種不尋常的機制將一種常見病原體——小麥銹菌的孢子從葉片中排出的能力。因此,他們給小麥植株接種了這種疾病,在植株的葉子上形成露水,然后用高速顯微鏡研究了隨之而來的作用。

      Here’s what they saw: the leaves are extremely hydrophobic—meaning water beads up to minimize contact with the surface. And when two or more drops touch, energy gets released in the form of a catapulting action, which "sneezes" the droplets into the air, several millimeters above the leaf surface. The droplets can then be picked up by light breezes or simply fall, and spread to other plants. The process is surprisingly effective at launching spores: the researchers figure each leaf can launch 100 spores per hour during a morning dew. The results—and photos of the jumping drops—are in the Journal of the Royal Society Interface. Saurabh Nath et al, ‘Sneezing’ plants: pathogen transport via jumping-droplet condensation

      他們的發現是這樣的:樹葉非常疏水,這意味著上面的水珠可以減少與表面的接觸。當兩顆或兩顆以上的水滴接觸時,能量以彈射動作的形式釋放出來,彈射動作將水滴“打噴嚏”到離葉子表面幾毫米高的空氣中。小水滴可以被微風吹起,也可以直接飄落下來,然后傳播到其他植物上。這個過程在發射孢子方面出奇地有效:研究人員發現,在晨露期間,每片葉子每小時能發射100個孢子。研究結果和跳高運動員的照片發表在《英國皇家學會界面》雜志上。

      Next, Boreyko and his team want to see what happens if they spray stuff on the leaves that changes the way dew forms. "If we change the wettability of the leaves so they're no longer super hydrophobic, now the dew drops will be unable to jump when they grow. They'll just sort of cling to the leaf surface and not be jumping anymore."Such treatment could perhaps put a stop to wheat sneezes, and slow down the transmission of disease.

      接下來,Boreyko和他的團隊想看看如果他們在葉子上噴灑改變露水形成方式的物質會發生什么。“如果我們改變樹葉的潤濕性,讓它們不再具有超強的疏水性,那么現在露珠在生長時就無法跳躍。”它們會粘在葉子表面,不再跳躍。“這樣的治療也許可以阻止小麥打噴嚏,減緩疾病的傳播

      Wheat Plants "Sneeze" and Spread Disease

      Humans can spread disease by sneezing. But less well known is the wheat plant's ability to do something strangely similar, from its leaves. "It's basically analogous to a human sneeze, in terms of, you have a very fast and sudden expulsion of droplets that contain the disease or pathogen inside of it, and they get thrown away from the surface."

      Jonathan Boreyko, a mechanical engineer at Virginia Tech. He and his team were studying the ability of wheat plants to expel spores of a common pathogen, the wheat rust fungus, from their leaves via this unusual mechanism. So they inoculated wheat plants with the disease, created dew on the plants' leaves, and then studied the ensuing action with high speed microscopy.

      Here’s what they saw: the leaves are extremely hydrophobic—meaning water beads up to minimize contact with the surface. And when two or more drops touch, energy gets released in the form of a catapulting action, which "sneezes" the droplets into the air, several millimeters above the leaf surface. The droplets can then be picked up by light breezes or simply fall, and spread to other plants. The process is surprisingly effective at launching spores: the researchers figure each leaf can launch 100 spores per hour during a morning dew. The results—and photos of the jumping drops—are in the Journal of the Royal Society Interface. Saurabh Nath et al, ‘Sneezing’ plants: pathogen transport via jumping-droplet condensation

      Next, Boreyko and his team want to see what happens if they spray stuff on the leaves that changes the way dew forms. "If we change the wettability of the leaves so they're no longer super hydrophobic, now the dew drops will be unable to jump when they grow. They'll just sort of cling to the leaf surface and not be jumping anymore."Such treatment could perhaps put a stop to wheat sneezes, and slow down the transmission of disease.


      內容來自 VOA英語學習網http://www.fb881.com/show-8762-241760-1.html
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