题型：阅读理解 题类：常考题 难易度：普通
广东省佛山市第一中学2018-2019学年高二上学期英语第一次段考试卷
Like people, plants experience stress. And also, like people, the response to that stress can determine success.
Bad environmental conditions, such as drought, flood, heat and other stresses, affect yields (产量) more than crop pests and diseases. We are trying to find a way to equip plants with the ability to tolerate environmental stress and maintain high yields, said Stephen Howell, a professor of genetics and cell biology.
Plant cells produce proteins (蛋白质) and ship them to different parts of the cell. Under normal conditions, these proteins are folded into their normal, healthy structures as they are produced. When a plant is under stress, its cells produce poorly folded or unfolded proteins. Then a built-in system senses this and “sets off an alarm in the cell,” said Howell.
In response to the alarm, another protein (IRE1) starts working and creates a different process which activates (激活) the stress response genes whose products bring about defensive measures that help the plant survive.
“As it turns out, responses that are activated under stress conditions actually inhibit the growth of plants,” said Howell. “This allows them to preserve their energy to survive the stress conditions.”
For plants in the wild, this response is a help for survival, he said. In production of agriculture crops, however, this response reduces yields.
“You don't want crop plants to stop growing,” Howell said. “You want them to continue to grow and produce even though they are under stress.”
With the new understanding of this stress response, the next step may be to silence the alarm system, said Howell. “What may be important is to disable some of these stress responses. That may make the plant more productive under stress conditions.”
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