Ithappenseveryspring.Flowerscomeouteverywhereonthesamed...
問題詳情:
It happens every spring. Flowers come out everywhere on the same day. But how do plants “know” when to flower?
For years, it has been a difficult question for scientists. But a US research group may have finally answered it—the secret lies in a protein(蛋白質)called FKF1. This helps plants to know when the days become long and when they get short. Then they can tell the seasons are changing.
Researchers found the FKF1 protein when they were studying a plant called Arabidopsis(擬南芥). It is sensitive(敏感的)to sunlight, and can be made active by sunlight.
Plants produce this protein every day in the late afternoon all year. If there is no light at this time, for example in winter when the sun goes down early, the protein won’t be active. But when spring comes and the days get longer, the FKF1 protein can be made active by day light and the plants “know” it is time to flower. “If there is light in the late afternoon, plants will know that the days are getting longer and that it is the best time for flowers to come out,” explained Takato Imaizumi, leader of study. But when conditions are poor for growing, such as during autumn or winter when the weather is cold and days are short, plants won’t flower.
Although researchers have only studied how the FKF1 protein works in the Arabidopsis, they believe that it is the same with many other plants, including crops such as rice and wheat. This could be useful to the agricultural industry.
“If we can control when flowers come out, we might be able to increase crop production,” Imaizumi said.
1. The passage is mainly about ____.
A. how plants “know” when to flower B. what people can do with plants
C. how seasons are changing D. what kind of plant Arabidopsis is
2. Scientists found the FKF1 protein when they were____.
A. answering a question B. controlling the clours of flowers
C. planting flowers in the garden D. studying a plant called Arabidopsis
3. The best time for flowers to come out is when____.
A. it rains in spring B. there is light in the late afternoon
C. it is getting dark D. the sun goes down early
4. Scientists believe that____. A. other plants also know when to flowers
B. flowers are more valuable than fruits and vegetables
C. people have known how to control when flowers come out
D. if the weather is cold and days are short, plants will flower
【回答】
1.A 2.D 3.B 4. A
知識點:日常生活類
題型:閱讀理解
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如圖中,A、B、C、D、E是單質,G、H、I、F是B、C、D、E分別和A形成的二元化合物,已知:①反應C+G ...
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用若干個體積爲1的正方體搭成一個幾何體,其正視圖、側視圖都是如圖所示的圖形,則這個幾何體的最大體積與最小體積的...
問題詳情:用若干個體積爲1的正方體搭成一個幾何體,其正視圖、側視圖都是如圖所示的圖形,則這個幾何體的最大體積與最小體積的差是()A.2B.3C.4D.5【回答】解析:由正視圖、側視圖可知,此幾何體的體積最小時,底層有5個小正方體,上面有2個小正方體,共7個小正方體;體積最大時,底...
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—Thestateofillnessiscomplicated.Weneedanexperienceddoct...
問題詳情:—Thestateofillnessiscomplicated.Weneedanexperienceddoctor.—Whomwouldyouliketohave____? A.sentfor B.sendfor C.tosendfor D.beens...
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“吃得營養、吃出健康”是人們普遍的飲食追求,下列說法不正確的是A.人每天都應攝入一定量的蛋白質B.過量食用油脂...
問題詳情:“吃得營養、吃出健康”是人們普遍的飲食追求,下列說法不正確的是A.人每天都應攝入一定量的蛋白質B.過量食用油脂能使人發胖,故應禁止攝入油脂C.糖類是人體能量的重要來源D.過量攝入微量元素不利於健康【回答】B知識點:各地中考題型:選擇題...
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