剑桥雅思16Test3Passage3阅读原文翻译Plant thermometer triggers springtime growth

剑桥雅思16 Test3 Passage3阅读原文翻译

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

植物细胞中的感光分子被发现还有另外一项作用，在夜晚降临时充当温度计，让植物可以读取季节性的温度变化。科学家认为，这一发现能够帮助培育更加适应气候变化所带来的温度变化的农作物。

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.

由剑桥大学领导的国际科学家团队发现，植物中的“温度计”分子让他们可以根据季节温度的变化生长。研究者发现了一种叫做光敏素的分子–白天的时候植物用它来检测光照–会在夜晚改变自己的功能，变成分子温度计量器，测量晚上的热度。

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.

发表于《科学》杂志上的这些新发现表明，光敏素控制基因变化，以应对掌管植物生长的温度和光照。

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.

科学家比较了光敏素和温度计中的水印，发现这些分子晚上会改变形态，变化的速度“与温度直接相关”。温度越高，分子变化速度越快–刺激植物生长。

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.

农民和园艺师几百年前就知道植物对温度反应灵敏：温暖的冬天会促使树木和花朵早早发芽。人们长久以来都用这一现象来预测来年的天气和收获时间。最近的研究首次明确了植物内部分子回应温度的机制。该机制引发我们在冬天末尾渴望见到的春天的嫩芽。

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.’

在由于气候变化，天气和温度注定变得更加难以预测的情况下，研究人员认为这一发现–光感分子也作为植物细胞内部的温度计–能够帮助我们培育更加顽强的农作物。“据估计，农业产出需要在2050年时翻倍，但气候变化对达成这一目标构成严峻的威胁。诸如小麦和大米这样的主要农作物对高温很敏感。气温每上升1度，粮食产量就会下降10%”，剑桥Sainsbury实验室首席研究员Philip Wigge说。“发现植物中感受温度的分子有可能能够帮助我们更快地培育出更加适应温度上升和气候变化的农作物”。

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.

在活跃状态下，光敏素分子与DNA结合在一起，限制植物生长。白天，阳光激活这些分子，降低增长速度。如果一株植物发现自己位于阴影中，光敏素会迅速钝化，使得它能够更快地增长以再次找到阳光。这就是植物互相竞争以逃脱彼此阴影的机制。“受光驱动的光敏素活动的变化非常快，还不到1秒”，Wigge说。

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，晚上的时候就是另一个故事了。太阳下山后，这些分子并没有快速钝化，而是逐渐从激活状态变成休眠状态。这一过程被称为“黑夜回归”。“就像水银在温度计中上升一样，光敏素在晚上回归休眠状态的速度是温度的直接体现”，Wigge说。

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.

“温度越低，光敏素回归休眠状态的速度就越慢，因此这些分子会有更多的时间处于活跃状态，压制植物生长。这就是植物为什么在冬天长得更慢一些的原因。温暖的温度会加速黑夜回归，以便光敏素快速到达不活跃状态，将它们自己与植物的DNA分离开来，让基因得以表达，植物恢复生长”。Wigge认为光敏素的温度感知能力出现于进化晚期，加入已经被用于在夜晚生长的生物网络。

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长作为季节的标志。其他植物，比如黄水仙，对温度很敏感，能够在温暖的冬季提前几个月开花。事实上，光敏素双重功能的发现为一句众所周知的、用来预测即将到来的季节的习语提供了科学依据：如果梣树先发芽，那夏天雨水会很多，而如果橡树先发芽，那夏天雨水将很少。

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解释道：“橡树更多地依赖温度，有可能利用光敏素作为温度计来决定生长。而梣树则依赖日长以决定自己随季节变化的节奏。更加温暖的春季，以及随之而来的更可能出现的炎热的夏季会导致橡树比梣树更早发芽。寒冷的春天会造成相反的情况。正如英国人所熟知的，冷一点的夏天很有可能阴雨连绵。

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.

这些新的发现是一项长达12年的研究的成果。其参与人员包括来自德国、阿根廷和美国的科学家，以及剑桥大学自己的团队。具体工作通过模型系统进行，使用了一种叫做鼠耳芥的芥菜属植物。但Wigge说，感知温度所必需的光敏素基因在农作物中也存在。“如今植物基因领域最新的进展意味着科学家能够快速找到控制农作物中这些过程的基因片段，甚至使用精准的分子手术刀改变他们的活动状态”，Wigge补充到。“剑桥在进行这项研究方面具有独特的优势，因为我们附近存在优秀的合作人员。他们从事植物生物更偏应用方面的研究，能够帮助我们将这一崭新的知识应用于实践”。