2018年06月六级第2套长篇阅读匹配原文翻译及答案

A) Ever since humanity began to farm our own food, we've faced the unpredictable rain that is both friend and enemy. It comes and goes without much warning, and a field of lush (茂盛的) leafy greens one year can dry up and blow away the next. Food security and fortunes depend on sufficient rain, and nowhere more so than in Africa, where 96% of farmland depends on rain instead of the irrigation common in more developed places. It has consequences : South Africa's ongoing drought— the worst in three decades— will cost at least a quarter of its corn crop this year.

自人类开始种植粮食以来，我们一直面临着既友好又敌对的不可预测的雨水。它来去无常，一片茂盛的绿叶蔬菜田可能在下一年就干枯并被风吹走。粮食安全和财富依赖于充足的雨水，这一点在非洲尤为突出，那里96%的农田依赖雨水而非更发达地区常见的灌溉。其后果是：南非持续的干旱——三十年来最严重的一次——将使其今年玉米作物损失至少四分之一。

B) Biologist Jill Farrant of the University of Cape Town in South Africa says that nature has plenty of answers for people who want to grow crops in places with unpredictable rainfall. She is hard at work finding a way to take traits from rare wild plants that adapt to extreme dry weather and use them in food crops. As the earth's climate changes and rainfall becomes even less predictable in some places, those answers will grow even more valuable. "The type of farming I'm aiming for is literally so that people can survive as it's going to get more and more dry," Farrant says.

南非开普敦大学的生物学家吉尔·法伦特表示，对于那些想在降雨不可预测的地方种植作物的人来说，大自然有许多答案。她正在努力寻找一种方法，从适应极端干旱天气的稀有野生植物中提取特性，并将其应用于粮食作物。随着地球气候变化和某些地区降雨变得更加不可预测，这些答案将变得更有价值。法伦特说：“我所追求的农业类型，字面意义上是为了让人们在日益干旱的环境中生存下来。”

C) Extreme conditions produce extremely tough plants. In the rusty red deserts of South Africa, steep-sided rocky hills called inselbergs rear up from the plains like the bones of the earth. The hills are remnants of an earlier geological era, scraped bare of most soil and exposed to the elements. Yet on these and similar formations in deserts around the world, a few fierce plants have adapted to endure under ever-changing conditions.

极端条件产生极其坚韧的植物。在南非锈红色的沙漠中，陡峭的岩石山丘称为岛山，像大地的骨架一样从平原上突起。这些山丘是更早地质时代的遗迹，被剥离了大部分土壤，暴露在自然环境中。然而，在这些以及世界各地沙漠中的类似地貌上，一些顽强的植物已经适应了在不断变化的条件下生存。

D) Farrant calls them resurrection plants (复苏植物). During months without water under a harsh sun. They wither, shrink and contract until they look like a pile of dead gray leaves. But rainfall can revive them in a matter of hours. Her time-lapse (间歇性拍摄的) videos of the revivals look like someone playing a tape of the plant's death in reverse.

法伦特称它们为复苏植物。在严酷阳光下数月无水期间，它们枯萎、收缩，直到看起来像一堆死灰色的叶子。但降雨可以在几小时内使它们复苏。她拍摄的复苏过程的时间推移视频看起来像有人倒放了植物死亡的录像带。

E) The big difference between "drought-tolerant" plants and these tough plants: metabolism. Many different kinds of plants have developed tactics to weather dry spells. Some plants store reserves of water to see them through a drought ; others send roots deep down to subsurface water supplies. But once these plants use up their stored reserve or tap out the underground supply, they cease growing and start to die. They may be able to handle a drought of some length, and many people use the term "drought tolerant" to describe such plants, but they never actually stop needing to consume water, so Farrant prefers to call them drought resistant.

“耐旱”植物与这些坚韧植物之间的主要区别在于新陈代谢。许多不同种类的植物已经发展出应对干旱期的策略。一些植物储存水分储备以度过干旱；另一些植物将根深扎以获取地下水供应。但一旦这些植物用尽储存的储备或耗尽地下供应，它们就会停止生长并开始死亡。它们可能能够应对一定长度的干旱，许多人用“耐旱”来形容这类植物，但它们实际上从未停止需要消耗水分，所以法伦特更倾向于称它们为抗旱植物。

F) Resurrection plants, defined as those capable of recovering from holding less than 0.1 grams of water per gram of dry mass, are different. They lack water-storing structures, and their existence on rock faces prevents them from tapping groundwater, so they have instead developed the ability to change their metabolism. When they detect an extended dry period, they divert their metabolisms, producing sugars and certain stress-associated proteins and other materials in their tissues. As the plant dries, these resources take on first the properties of honey, then rubber, and finally enter a glass-like state that is "the most stable state that the plant can maintain," Farrant says. That slows the plant's metabolism and protects its dried-out tissues. The plants also change shape, shrinking to minimize the surface area through which their remaining water might evaporate. They can recover from months and years without water, depending on the species.

复苏植物，定义为那些能够从每克干物质持有少于0.1克水分的状态中恢复的植物，是不同的。它们缺乏储水结构，并且它们在岩石表面的存在阻止了它们获取地下水，因此它们反而发展出了改变新陈代谢的能力。当它们探测到延长的干旱期时，它们会改变新陈代谢，在组织中产生糖类、某些应激相关蛋白质和其他物质。随着植物干燥，这些资源首先具有蜂蜜的特性，然后是橡胶，最后进入玻璃状状态，这是“植物能够维持的最稳定状态”，法伦特说。这减缓了植物的新陈代谢并保护其干燥组织。植物还会改变形状，收缩以最小化剩余水分可能蒸发的表面积。根据物种不同，它们可以从数月甚至数年的无水状态中恢复。

G) What else can do this dry-out-and-revive trick? Seeds-almost all of them. At the start of her career, Farrant studied. recalcitrant seeds (执拗性种子)," such as avocados, coffee and lychee. While tasty, such seeds are delicate--they cannot bud and grow if they dry out (as you may know if you've ever tried to grow a tree from an avocado pit). In the seed world, that makes them rare, because most seeds from flowering plants are quite robust. Most seeds can wait out the dry, unwelcoming seasons until conditions are right and they sprout (发芽). Yet once they start growing, such plants seem not to retain the ability to hit the pause button on metabolism in their stems or leaves.

还有什么能玩转这种干枯与复苏的把戏？种子——几乎所有种子。在职业生涯初期，法伦特研究了执拗性种子，如鳄梨、咖啡和荔枝。虽然美味，但这类种子很脆弱——如果它们干燥了，就不能发芽生长（如果你曾尝试用鳄梨核种树，你可能知道这一点）。在种子世界中，这使得它们很罕见，因为开花植物的大部分种子相当坚韧。大多数种子可以等待干燥、不友好的季节过去，直到条件合适时发芽。然而，一旦它们开始生长，这些植物似乎不再保留其茎或叶中按下新陈代谢暂停按钮的能力。

H) After completing her Ph. D. on seeds, Farrant began investigating whether it might be possible to isolate the properties that make most seeds so resilient (迅速恢复活力的) and transfer them to other plant tissues. What Farrant and others have found over the past two decades is that there are many genes involved in resurrection plants' response to dryness. Many of them are the same that regulate how seeds become dryness-tolerant while still attached to their parent plants. Now they are trying to figure out what molecular signaling processes activate those seed-building genes in resurrection plants— and how to reproduce them in crops. "Most genes are regulated by a master set of genes,"Farrant says. "We're looking at gene promoters and what would be their master switch."

完成关于种子的博士学位后，法伦特开始研究是否有可能分离出使大多数种子如此坚韧的特性，并将它们转移到其他植物组织中。法伦特和其他人在过去二十年中发现，有许多基因参与了复苏植物对干旱的反应。其中许多基因与调控种子在仍附着于母体植物时如何变得耐旱的基因相同。现在，他们正在试图弄清楚哪些分子信号过程激活了复苏植物中的这些种子构建基因——以及如何在作物中重现它们。法伦特说：“大多数基因由一组主基因调控。我们正在研究基因启动子及其主开关。”

I) Once Farrant and her colleagues feel they have a better sense of which switches to throw, they will have to find the best way to do so in useful crops. "I'm trying three methods of breeding," Farrant says: conventional, genetic modification and gene editing. She says she is aware that plenty of people do not want to eat genetically modified crops, but she is pushing ahead with every available tool until one works. Farmers and consumers alike can choose whether or not to use whichever version prevails: "I'm giving people an option."

一旦法伦特和她的同事们觉得他们更清楚该启动哪些开关，他们将不得不找到在有用作物中实现这一目标的最佳方法。法伦特说：“我正在尝试三种育种方法：常规育种、基因改造和基因编辑。她说她意识到许多人不想吃转基因作物，但她正在使用每种可用工具推进，直到其中一种起作用。农民和消费者都可以选择是否使用哪个版本占优势：“我在给人们一个选择。”

J) Farrant and others in the resurrection business got together last year to discuss the best species of resurrection plant to use as a lab model. Just like medical researchers use rats to test ideas for human medical treatments, botanists use plants that are relatively easy to grow in a lab or greenhouse setting to test their ideas for related species. The Queensland rock violet is one of the best studied resurrection plants so far, with a draft genome (基因图谱) published last year by a Chinese team. Also last year, Farrant and colleagues published a detailed molecular study of another candidate, Xerophyta viscosa, a tough-as-nail south African plant with lily-like flowers, and she says that a genome is on the way. one or both of these models will help researchers test their ideas — so far mostly done in the lab— on test plots.

法伦特和其他从事复苏植物研究的人去年聚在一起，讨论用作实验室模型的最佳复苏植物物种。就像医学研究人员用老鼠测试人类医疗想法一样，植物学家使用相对容易在实验室或温室环境中生长的植物来测试他们对相关物种的想法。昆士兰岩紫罗兰是迄今为止研究最深入的复苏植物之一，去年一个中国团队发表了其草图基因组。同样在去年，法伦特和同事发表了对另一个候选物种Xerophyta viscosa的详细分子研究，这是一种坚韧的南非植物，花朵似百合，她说基因组即将完成。这些模型中的一种或两种将帮助研究人员在测试地块上测试他们的想法——到目前为止主要在实验室进行。

K) Understanding the basic science first is key. There are good reasons why crop plants do not use dryness defenses already. For instance, there's a high energy cost in switching from a regular metabolism to an almost-no-water metabolism. It will also be necessary to understand what sort of yield farmers might expect and to establish the plant's safety. "The yield is never going to be high, "Farrant says, so these plants will be targeted not at Iowa farmers trying to squeeze more cash out of high-yield fields, but subsistence farmers who need help to survive a drought like the present one in South Africa." My vision is for the subsistence farmer," Farrant says. "I'm targeting crops that are of African value."

首先理解基础科学是关键。作物植物不使用干旱防御有充分的理由。例如，从常规新陈代谢切换到几乎无水的新陈代谢具有高能量成本。还需要了解农民可能期望的产量，并确定植物的安全性。法伦特说：“产量永远不会高，”因此这些植物将针对的不是试图从高产田地榨取更多现金的爱荷华州农民，而是需要帮助以度过如南非当前干旱的自给自足农民。法伦特说：“我的愿景是针对自给自足的农民。”“我针对的是具有非洲价值的作物。”