久久亚洲国产成人影院-久久亚洲国产的中文-久久亚洲国产高清-久久亚洲国产精品-亚洲图片偷拍自拍-亚洲图色视频

您現(xiàn)在的位置: Language Tips> Audio & Video> Special Speed News  
   
 





 
Researchers seek drought-resistant crops
[ 2008-06-03 10:54 ]

 

Download

This is the VOA Special English Agriculture Report.

One cause of the current food crisis is drought. Food prices are high in part because of dry weather in places as far distant as Spain and Australia.

Around the world, the amount of land affected by drought has doubled in the past thirty years. So says the National Center for Atmospheric Research in the United States. And scientists concerned about climate change believe it will cause more drought in many areas in the future.

A lot of research is going into efforts to develop drought-resistant crops. One project involves tobacco plants genetically engineered to keep their leaves during water shortages.

Eduardo Blumwald and Rosa Rivero at the University of California, Davis, led a team from the United States, Japan and Israel. Rosa Rivero says they chose tobacco because it has big leaves. Also, it grows fast and has structural similarities with some other plants.

The researchers did an experiment with two groups of tobacco plants. They worked with a set of normal plants and a set of transgenic plants. These had a gene added to interfere with the biological causes of leaf loss during drought.

The researchers put all the plants in a greenhouse to grow under normal conditions for forty days. Then, for fifteen days after that, the plants did not receive any water.

The normal plants lost their green color. Finally, they lost their leaves. But the researchers say the transgenic plants kept their leaves and their color.

After the fifteen dry days, all the plants were watered again for a week. The transgenic plants returned to normal growth, and their seed production was close to normal. But the other plants all died.

Rosa Rivero says the transgenic plants kept a relatively high water level. They also continued to produce energy during the dry period, although at a reduced level. The amount of seeds they produced was close to normal.

In addition, the researchers found that the plants could survive on only thirty percent of the normal amount of irrigation water. Yield loss was minor, they said.

The findings appeared late last year in the Proceedings of the National Academy of Sciences. The University of California has applied for patent protection for the technology.

The researchers expect to move forward with field testing of the transgenic tobacco in late August. They hope for similar results with crops like tomatoes, rice, wheat and cotton.

And that's the VOA Special English Agriculture Report, written by Jerilyn Watson. I’m Steve Ember.

(Source: VOA 英語點津姍姍編輯)

 
英語點津版權說明:凡注明來源為“英語點津:XXX(署名)”的原創(chuàng)作品,除與中國日報網(wǎng)簽署英語點津內容授權協(xié)議的網(wǎng)站外,其他任何網(wǎng)站或單位未經(jīng)允許不得非法盜鏈、轉載和使用,違者必究。如需使用,請與010-84883631聯(lián)系;凡本網(wǎng)注明“來源:XXX(非英語點津)”的作品,均轉載自其它媒體,目的在于傳播更多信息,其他媒體如需轉載,請與稿件來源方聯(lián)系,如產生任何問題與本網(wǎng)無關;本網(wǎng)所發(fā)布的歌曲、電影片段,版權歸原作者所有,僅供學習與研究,如果侵權,請?zhí)峁┌鏅嘧C明,以便盡快刪除。
相關文章 Related Story
 
 
 
本頻道最新推薦
 
Walking in the US first lady's shoes
“準確無誤”如何表達
英國新晉超女蘇珊大媽改頭換面
豬流感 swine flu
你有l(wèi)ottery mentality嗎
翻吧推薦
 
論壇熱貼
 
別亂扔垃圾。怎么譯這個亂字呀?
橘子,橙子用英文怎么區(qū)分?
看Gossip Girl學英語
端午節(jié)怎么翻譯?
母親,您在天堂還好嗎?

 

主站蜘蛛池模板: 亚洲一区二区三区欧美 | 日韩色网站 | 国产一区二区在线观看视频 | 美女曰皮| 99久久这里只精品国产免费 | 精品三级在线观看 | 在线免费观看一区二区三区 | 玖玖玖精品视频免费播放 | 99国内精品 | 国产精品天天爽夜夜欢张柏芝 | 精品免费久久 | 日本在线理论片 | 精品免费久久久久欧美亚一区 | 色屁屁一区二区三区视频国产 | 99久久精品免费看国产免费软件 | 黄在线网站 | 99视频在线观看视频一区 | 老司机成人免费精品视频 | 性感美女一级毛片 | 玖玖视频精品 | 国产区一区二 | 亚洲加勒比 | 亚洲国产精品成人午夜在线观看 | 高跟丝袜美女一级毛片 | 五月天激激婷婷大综合蜜芽 | 欧美黄色精品 | 特级a欧美孕妇做爰片毛片 特级a欧美做爰片毛片 | 国产高清一区二区三区四区 | 台湾黄三级高清在线观看播放 | 欧美成人三级网站在线观看 | 性日韩精品 | 高清韩国a级特黄毛片 | 一级一片 | www.欧美成人 | 日本全黄 | 久久精品中文字幕首页 | 亚洲精品一区二区三区在线播放 | 久久怡红院国产精品 | 国产精品理论片 | 亚洲精品高清国产一久久 | 好看毛片 |