您現在的位置: Language Tips> Audio & Video> Special Speed News  
       
     





     
    Fighting witchweed in African sorghum
    [ 2008-06-24 10:27 ]

    Download

    This is the VOA Special English Development Report.

    Farmers in Africa call the striga plant by the name witchweed. It grows a pleasant looking purple flower. But it attacks many crops in the grass family. Witchweed is among the few flowering weeds that act as parasites on other plants.

    Every year it causes six to seven billion dollars in damage to African grain sorghum. Sorghum is important to the local food supply. The witchweed steals water and nutrients from the roots and attacks the sorghum with a poisonous substance.

    Now, scientists say they have produced seeds that can protect sorghum crops from witchweed.

    Kassim Al-Katib is a weed expert at Kansas State University in the United States. Mitch Tuinstra is a genetics and plant-breeding expert formerly at Kansas State but now at Purdue University in Indiana.

    To deal with witchweed, they developed special sorghum-seed genes. These genes can accept carefully chosen chemical herbicides without being harmed. The researchers placed the herbicides on the sorghum seeds. Kassim al-Katib said the seeds kill the witchweed as the sorghum grows.

    Mitch Tuinstra directed greenhouse tests of the seeds in the Netherlands in two thousand five and two thousand six. Similar studies took place in field trials in Mali and in Niger. These studies showed the treatment to be highly successful.

    Mitch Tuinstra recently returned from Africa, where he met with agriculture experts. They are working to develop local kinds of sorghum that employ the genes. The project is a collective research program under the United States Agency for International Development.

    Witchweed has another unusual quality. It requires chemical signals from sorghum seeds to grow. If no sorghum seeds are present, the witchweed seeds can lie under the soil for years. The seeds begin to grow only when they receive the needed chemical signals.

    Witchweed seed capsules can hold four hundred to five hundred seeds. Winds and rain spread the parasite. The plant can reduce a farmer's crop. Or it can completely destroy many hectares of grain. Witchweed is very difficult to remove after it invades an area.

    Damage from the parasite is worst in dry soil with low fertility. It often strikes farmers who work the poorest land. This can mean disaster for people who already do not have enough to eat.

    And that's the VOA Special English Development Report, written by Jerilyn Watson.

    (來源:VOA 英語點津 Annabel 編輯)

     
    英語點津版權說明:凡注明來源為“英語點津:XXX(署名)”的原創作品,除與中國日報網簽署英語點津內容授權協議的網站外,其他任何網站或單位未經允許不得非法盜鏈、轉載和使用,違者必究。如需使用,請與010-84883631聯系;凡本網注明“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,請與稿件來源方聯系,如產生任何問題與本網無關;本網所發布的歌曲、電影片段,版權歸原作者所有,僅供學習與研究,如果侵權,請提供版權證明,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lottery 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,橙子用英文怎么區分?
    看Gossip Girl學英語
    端午節怎么翻譯?
    母親,您在天堂還好嗎?

     

    最近中文字幕2019高清免费 | 久久久久久亚洲精品无码| 在线观看免费中文视频| 东京热无码av一区二区| 无码夫の前で人妻を犯す中字| 无码人妻少妇伦在线电影| 亚洲AV无码1区2区久久| 亚洲av午夜国产精品无码中文字 | 国色天香中文字幕在线视频| 人妻丝袜中文无码av影音先锋专区 | 台湾无码AV一区二区三区| 日韩亚洲国产中文字幕欧美| 成年无码av片在线| 无码少妇一区二区性色AV| 无码AV动漫精品一区二区免费| 天天爽亚洲中文字幕| 久久伊人亚洲AV无码网站| 精品久久久久久无码专区不卡| 亚洲午夜无码久久久久| 色婷婷综合久久久久中文字幕| 色综合网天天综合色中文男男| 中文字幕在线无码一区| 精选观看中文字幕高清无码| 成人免费无码H在线观看不卡 | 久久午夜无码鲁丝片| 国产成人无码精品久久久性色| 五月丁香啪啪中文字幕| 人妻中文久久久久| 久久丝袜精品中文字幕| 国产中文字幕乱人伦在线观看 | 国内精品久久久人妻中文字幕 | 最近2018中文字幕免费视频| 亚洲一区二区三区在线观看精品中文 | 国产成年无码久久久免费| 欧美日韩毛片熟妇有码无码 | 无码AV中文字幕久久专区| 亚洲VA中文字幕无码一二三区| 无码中文人妻视频2019| 国产精品多人p群无码| 变态SM天堂无码专区| 无码专区6080yy国产电影|