作物的生长发育都有自己的“生物钟“调节机制，这来自于基因，所以对相关基因的发现，以及后续的改造可以帮助我们控制这一生长机制，从而可以使作物的耐受性改变，更加适宜于严酷的环境。新东方网托福频道为各位考生带来托福阅读素材：转基因作物，希望对大家的托福阅读提高有所帮助。
mustard n. 芥末;芥菜
molecular adj. [化学] 分子的
Exhausted adj. 疲惫的;耗尽的v. 耗尽
biological clock生物钟
yield n. 产量;收益vt. 屈服
manipulate vt. 操纵;操作;巧妙地处理
in tune with(与...)一致;(与...)协调
Changing Gene in Plant Could Yield More Crops
改变植物基因可以增加产量
Plants have a "biological clock" that tells them when to produce leaves, seeds and other growth. A new study says understanding that clock may help scientists develop crops that can feed a growing population in an increasingly warmer world.
Rob McClung is a scientist at Dartmouth College. He says scientists need to create ways to feed the nearly 10 billion people who will be living on Earth by the middle of the century.
He says estimates show that there will need to be an increase in the world food supply of about 50 to 60 percent in the next thirty-five years.
"And we're worried that the things that we've done to increase agricultural productivity may be becoming exhausted."
To find new ways to increase productivity, Mr. McClung examined the biological clocks of plants. He learned that different genes in plants affect the plant's clock.
He published his findings in the Proceedings of the National Academy of Sciences. He says he identified a gene called GIGANTEA in a common species of the plant called field mustard.
He discovered that the speed of the gene's development can affect when the plant produces. Mr. McClung says the gene also affects how the plant deals with extreme cold and high levels of salt.
"We want to be able to predict if you do this to the clock, you will do this to crop yield."
He says he hopes his research will give plant developers a molecular tool they can use to create a plant that can accept a higher level of salt or grow in a colder environment than usual.
"...we think that by manipulating the plant clock, we will be able to make plants that are better in tune with their environment and able to perform more effectively."
Experts say the current growth in the production of the world's major food crops -- corn, rice, wheat and soybeans -- will not be enough to feed the 9.5 billion people who will be living on Earth in 2050.
长难句：
1.A new study says understanding that clock may help scientists develop crops that can feed a growing population in an increasingly warmer world.
句子类型：宾语从句+定语从句
句子拆分：
宾语从句: understanding that clock may help scientists develop crops
定语从句: that can feed a growing population in an increasingly warmer world
翻译：一项新的研究表明：了解这种“生物钟“可以帮助研究者生产出在日益温暖气候中足够供给增长人口的作物。
2.He says he hopes his research will give plant developers a molecular tool they can use to create a plant( that can accept a higher level of salt or grow in a colder environment than usual).
句子类型：宾语从句+定语从句
句子拆分：
主干：He says…
宾语从句:he hopes his research will give plant developers a molecular tool they can use to create a plant
定语从句:that can accept a higher level of salt or grow in a colder environment than usual
翻译：他表示，他希望自己的研究结果可以给生产者一种分子水平的工具来用于生产可以耐高盐或者在高寒环境生长。
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