本篇文章共分 A-H 8 大段 (為配合題目出題，有些大段中包含 2 個小段)，從劍橋大學團隊的發現開始說明植物色素在白晝、夜間、冬季的運作原理，同時指出這種分子在農業培育上展有的重要性，並展望未來的進一步研究成果。

本篇考題英文原文與對應之中文翻譯整理如下。練習作答解題時若有對語意不清楚之處，請仔細查閱對照，以提升閱讀理解能力。

Plant 'Thermometer' Triggers Springtime Growth by Measuring Night-Time Heat 植物「溫度計」通過測量夜間熱量觸發春天的生長

1. 植物的溫度計分子

   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

   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.

   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.

   植物細胞中的一種光感受器分子被發現在天黑後具有作為溫度計的第二項工作—使植物能夠讀取季節性的溫度變化。科學家們說，此一發現可以幫助培育出對氣候變化導致的溫度有更強適應性的作物。

   由劍橋大學領導的一個國際科學家小組發現，植物中的「溫度計」分子使它們能夠根據季節性的溫度變化而發育。研究人員發現，被稱為植物色素的分子—植物在白天用此分子探測光線—在黑暗中實際上改變了它們的功能，成為測量夜晚熱量的細胞溫度計。

   發表在《科學》雜誌上的新發現顯示，植物色素控制著對溫度以及光的反應的基因開關，從而決定了植物的發育。

2. 夜晚效應

   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.

   科學家們說，在晚上，這些分子會改變狀態，它們變化的速度「與溫度成正比」，他們把植物色素比作溫度計中的水銀。天氣越暖和，分子變化越快—用以刺激植物生長。

3. 利用植物生長預測氣候

   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.

   幾百年來，農民和園丁們一直知道植物對溫度的反應：溫暖的冬天導致許多樹木和花朵提前發芽，人類長期以來一直用這種方法來預測來年的天氣和收穫時間。最新的研究首次指出了植物中對溫度有反應的分子機制—經常觸發我們渴望在冬末看到的春芽。

4. 培育作物的助力

   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.’

   研究人員說，由於氣候變化，天氣和溫度將變得更加不可預測，這種感光分子也作為植物細胞的內部溫度計的發現可以幫助我們培育出更堅韌的作物。「據估計，到 2050 年，農業產量將需要翻一番，但氣候變化是實現這一目標的主要威脅。小麥和水稻等主要農作物對高溫很敏感。溫度每升高一度，熱應力就會使作物產量減少約 10%。」劍橋大學 Sainsbury 實驗室的首席研究員 Philip Wigge博士說：「發現讓植物感知溫度的分子，有可能加速培育對熱應力和氣候變化有抵抗力的作物。」

5. 植物色素運作原理

   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.

   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.

   在活性狀態下，植物色素分子將自己與 DNA 結合，以限制植物生長。在白天，陽光會啟動這些分子，減緩生長。如果植物發現自己處於陰涼處，植物色素就會迅速失去活性—使植物能夠更快地生長，再次找到陽光。這就是植物如何競爭以逃避彼此帶來陰影。Wigge 說：「光驅動的植物色素活動的變化發生得非常快，不到一秒鐘。」

   然而，在晚上，情況就不一樣了。日落後，分子不是迅速失活，而是逐漸從活躍狀態變為不活躍狀態。這被稱為「黑暗回歸」。Wigge 說：「正如水銀在溫度計中上升一樣，植物色素在夜間恢復到非活性狀態的速度是對溫度的直接測量。」

6. 冬天時的運作

   ‘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，植物色素恢復到非活性的速度就越慢，因此這些分子在其活躍的、抑制生長的狀態下花費的時間就越長。這就是為什麼植物在冬天生長得比較慢。溫暖的溫度加速了黑暗回歸，因此植物色素迅速達到非活性狀態，並從植物的 DNA 中分離出來—使基因得以呈現，植物生長得以恢復。」Wigge 認為植物色素的溫度感應是在後期演化出來的，並與已經用於夜間停工期間基於光的生長的生物網路合用。

7. 科學發現驗證民謠

   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.

   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.’

   有些植物主要以白晝長短為指標來判斷季節。其他物種，如水仙花，對溫度相當敏感，在溫暖的冬天可以提前幾個月開花。事實上，植物色素的雙重作用的發現提供了長期以來用於預測未來季節的著名兒歌背後的科學依據：橡樹在白蠟之前，我們將有一個少雨季，白蠟在橡樹之前，我們將有一個多雨季。

   Wigge 解釋說。橡樹更依賴溫度，可能使用植物色素作為溫度計來決定發育，而白蠟樹則依靠測量日長來決定其季節性時間。一個較溫暖的春天，以及隨之而來可能性更大的炎熱夏天，將導致橡樹在白蠟樹之前落葉。寒冷的春天將看到相反的情況。英國人非常清楚，一個較冷的夏天很可能是一個多雨的夏天。

8. 未來發展

   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.’

   這些新發現是來自德國、阿根廷和美國以及劍橋團隊的科學家們12年研究的結晶。這項工作是在一個模型系統中完成的，使用的是一種叫做阿拉伯芥的植物，但是 Wigge 說溫度感應所需的植物色素基因在作物植物中也能找到。「植物遺傳學的最新進展現在意味著科學家們能夠迅速確定作物植物中控制這些過程的基因，甚至使用精確的分子『手術刀』來改變它們的活性。」Wigge 補充說：「劍橋大學在進行這種研究方面具有獨特的優勢，因為在我們身邊有傑出的合作者，他們在植物生物學上進行更多的應用研究，可以幫助我們將這種新知識轉移到該領域。」