劍橋雅思16Test3Passage3閱讀原文翻譯Plant thermometer triggers springtime growth

劍橋雅思16 Test3 Passage3閱讀原文翻譯

引言

A photoreceptor molecule in plant cells has been found to have a second job as a thermometer after dark–allowing plants to read seasonal temperature changes.Scientists say the discovery could help breed crops that are more resilient to the temperatures expected to result from climate change

植物細胞中的感光分子被發(fā)現(xiàn)還有另外一項作用，在夜晚降臨時充當溫度計，讓植物可以讀取季節(jié)性的溫度變化?？茖W家認為，這一發(fā)現(xiàn)能夠幫助培育更加適應氣候變化所帶來的溫度變化的農(nóng)作物。

A部分

An international team of scientists led by the University of Cambridge has discovered that the‘thermometer’molecule in plants enables them to develop according to seasonal temperature changes.Researchers have revealed that molecules called phytochromes–used by plants to detect light during the day–actually change their function in darkness to become cellular temperature gauges that measure the heat of the night.

由劍橋大學領導的國際科學家團隊發(fā)現(xiàn)，植物中的“溫度計”分子讓他們可以根據(jù)季節(jié)溫度的變化生長。研究者發(fā)現(xiàn)了一種叫做光敏素的分子–白天的時候植物用它來檢測光照–會在夜晚改變自己的功能，變成分子溫度計量器，測量晚上的熱度。

The new findings,published in the journal Science,show that phytochromes control genetic switches in response to temperature as well as light to dictate plant development.

發(fā)表于《科學》雜志上的這些新發(fā)現(xiàn)表明，光敏素控制基因變化，以應對掌管植物生長的溫度和光照。

B部分

At night,these molecules change states,and the pace at which they change is‘directly proportional to temperature’,say scientists,who compare phytochromes to mercury in a thermometer.The warmer it is,the faster the molecular change–stimulating plant growth.

科學家比較了光敏素和溫度計中的水印，發(fā)現(xiàn)這些分子晚上會改變形態(tài)，變化的速度“與溫度直接相關”。溫度越高，分子變化速度越快–刺激植物生長。

C部分

Farmers and gardeners have known for hundreds of years how responsive plants are to temperature:warm winters cause many trees and flowers to bud early,something humans have long used to predict weather and harvest times for the coming year.The latest research pinpoints for the first time a molecular mechanism in plants that reacts to temperature–often triggering the buds of spring we long to see at the end of winter.

農(nóng)民和園藝師幾百年前就知道植物對溫度反應靈敏：溫暖的冬天會促使樹木和花朵早早發(fā)芽。人們長久以來都用這一現(xiàn)象來預測來年的天氣和收獲時間。最近的研究首次明確了植物內(nèi)部分子回應溫度的機制。該機制引發(fā)我們在冬天末尾渴望見到的春天的嫩芽。

D部分

With weather and temperatures set to become ever more unpredictable due to climate change,researchers say the discovery that this light-sensing molecule also functions as the internal thermometer in plant cells could help us breed tougher crops.‘It is estimated that agricultural yields will need to double by 2050,but climate change is a major threat to achieving this.Key crops such as wheat and rice are sensitive to high temperatures.Thermal stress reduces crop yields by around 10%for every one degree increase in temperature,’says lead researcher Dr Philip Wigge from Cambridge’s Sainsbury Laboratory.‘Discovering the molecules that allow plants to sense temperature has the potential to accelerate the breeding of crops resilient to thermal stress and climate change.’

在由于氣候變化，天氣和溫度注定變得更加難以預測的情況下，研究人員認為這一發(fā)現(xiàn)–光感分子也作為植物細胞內(nèi)部的溫度計–能夠幫助我們培育更加頑強的農(nóng)作物?！皳?jù)估計，農(nóng)業(yè)產(chǎn)出需要在2050年時翻倍，但氣候變化對達成這一目標構成嚴峻的威脅。諸如小麥和大米這樣的主要農(nóng)作物對高溫很敏感。氣溫每上升1度，糧食產(chǎn)量就會下降10%”，劍橋Sainsbury實驗室首席研究員Philip Wigge說。“發(fā)現(xiàn)植物中感受溫度的分子有可能能夠幫助我們更快地培育出更加適應溫度上升和氣候變化的農(nóng)作物”。

E部分

In their active state,phytochrome molecules bind themselves to DNA to restrict plant growth.During the day,sunlight activates the molecules,slowing down growth.If a plant finds itself in shade,phytochromes are quickly inactivated enabling it to grow faster to find sunlight again.This is how plants compete to escape each other’s shade.‘Light-driven changes to phytochrome activity occur very fast,in less than a second,’says Wigge.

在活躍狀態(tài)下，光敏素分子與DNA結合在一起，限制植物生長。白天，陽光激活這些分子，降低增長速度。如果一株植物發(fā)現(xiàn)自己位于陰影中，光敏素會迅速鈍化，使得它能夠更快地增長以再次找到陽光。這就是植物互相競爭以逃脫彼此陰影的機制?！笆芄怛寗拥墓饷羲鼗顒拥淖兓浅？?，還不到1秒”，Wigge說。

At night,however,it’s a different story.Instead of a rapid deactivation following sundown,the molecules gradually change from their active to inactive state.This is called‘dark reversion’.‘Just as mercury rises in a thermometer,the rate at which phytochromes revert to their inactive state during the night is a direct measure of temperature,’says Wigge.

然而，晚上的時候就是另一個故事了。太陽下山后，這些分子并沒有快速鈍化，而是逐漸從激活狀態(tài)變成休眠狀態(tài)。這一過程被稱為“黑夜回歸”?！熬拖袼y在溫度計中上升一樣，光敏素在晚上回歸休眠狀態(tài)的速度是溫度的直接體現(xiàn)”，Wigge說。

F部分

‘The lower the temperature,the slower the rate at which phytochromes revert to inactivity,so the molecules spend more time in their active,growth-suppressing state.This is why plants are slower to grow in winter.Warm temperatures accelerate dark reversion,so that phytochromes rapidly reach an inactive state and detach themselves from the plant’s DNA–allowing genes to be expressed and plant growth to resume.’Wigge believes phytochrome thermo-sensing evolved at a later stage,and co-opted the biological network already used for light-based growth during the downtime of night.

“溫度越低，光敏素回歸休眠狀態(tài)的速度就越慢，因此這些分子會有更多的時間處于活躍狀態(tài)，壓制植物生長。這就是植物為什么在冬天長得更慢一些的原因。溫暖的溫度會加速黑夜回歸，以便光敏素快速到達不活躍狀態(tài)，將它們自己與植物的DNA分離開來，讓基因得以表達，植物恢復生長”。Wigge認為光敏素的溫度感知能力出現(xiàn)于進化晚期，加入已經(jīng)被用于在夜晚生長的生物網(wǎng)絡。

G部分

Some plants mainly use day length as an indicator of the season.Other species,such as daffodils,have considerable temperature sensitivity,and can flower months in advance during a warm winter.In fact,the discovery of the dual role of phytochromes provides the science behind a well-known rhyme long used to predict the coming season:oak before ash we’ll have a splash,ash before oak we’re in for a soak.

一些植物主要使用日長作為季節(jié)的標志。其他植物，比如黃水仙，對溫度很敏感，能夠在溫暖的冬季提前幾個月開花。事實上，光敏素雙重功能的發(fā)現(xiàn)為一句眾所周知的、用來預測即將到來的季節(jié)的習語提供了科學依據(jù)：如果梣樹先發(fā)芽，那夏天雨水會很多，而如果橡樹先發(fā)芽，那夏天雨水將很少。

Wigge explains:‘Oak trees rely much more on temperature,likely using phytochromes as thermometers to dictate development,whereas ash trees rely on measuring day length to determine their seasonal timing.A warmer spring,and consequently a higher likeliness of a hot summer,will result in oak leafing before ash.A cold spring will see the opposite.As the British know only too well,a colder summer is likely to be a rain-soaked one.’

Wigge解釋道：“橡樹更多地依賴溫度，有可能利用光敏素作為溫度計來決定生長。而梣樹則依賴日長以決定自己隨季節(jié)變化的節(jié)奏。更加溫暖的春季，以及隨之而來的更可能出現(xiàn)的炎熱的夏季會導致橡樹比梣樹更早發(fā)芽。寒冷的春天會造成相反的情況。正如英國人所熟知的，冷一點的夏天很有可能陰雨連綿。

H部分

The new findings are the culmination of twelve years of research involving scientists from Germany,Argentina and the US,as well as the Cambridge team.The work was done in a model system,using a mustard plant called Arabidopsis,but Wigge says the phytochrome genes necessary for temperature sensing are found in crop plants as well.‘Recent advances in plant genetics now mean that scientists are able to rapidly identify the genes controlling these processes in crop plants,and even alter their activity using precise molecular“scalpels”‘,adds Wigge.“Cambridge is uniquely well-positioned to do this kind of research as we have outstanding collaborators nearby who work on more applied aspects of plant biology,and can help us transfer this new knowledge into the field.

這些新的發(fā)現(xiàn)是一項長達12年的研究的成果。其參與人員包括來自德國、阿根廷和美國的科學家，以及劍橋大學自己的團隊。具體工作通過模型系統(tǒng)進行，使用了一種叫做鼠耳芥的芥菜屬植物。但Wigge說，感知溫度所必需的光敏素基因在農(nóng)作物中也存在?！叭缃裰参锘蝾I域最新的進展意味著科學家能夠快速找到控制農(nóng)作物中這些過程的基因片段，甚至使用精準的分子手術刀改變他們的活動狀態(tài)”，Wigge補充到?！皠蛟谶M行這項研究方面具有獨特的優(yōu)勢，因為我們附近存在優(yōu)秀的合作人員。他們從事植物生物更偏應用方面的研究，能夠幫助我們將這一嶄新的知識應用于實踐”。

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