Ever wonder where seedless fruits come from?
文章来源: 文章作者: 发布时间:2009-06-16 07:18 字体: [ ]  进入论坛
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This is the VOA Special English Agriculture Report.

These days, if we hear about two different plants being combined, the first thing we think of might is modern biotechnology. But the low-technology process of grafting2 remains3 an extremely important form of genetic4 engineering in agriculture.

Many kinds of plants are grown not from seeds but from pieces cut from existing plants. Farmers cut branches or buds, young growths, from one plant and place them on a related kind of plant.

The branch or bud that isgraftedis called a scion6 [pronounced SY-uhn]. The plant that accepts the graft1 is called the root stock.

Over time, the parts from the two plants grow together. The grafted5 plant begins to produce the leaves and fruit of the scion, not the root stock.

A graft can be cut in several ways. A cleft7 graft, for example, requires a scion with several buds on it. The bottom of the scion is cut in the shape of the letter V. A place is cut in the root stock to accept the scion.

The scion is then securely placed into the cut on the root stock. Material called a growth medium is put on the joint8 to keep it wet and help the growth.

Grafting can join scions9 with desirable qualities to root stock that is strong and resists disease and insects. Smaller trees can be grafted with older scions.

The United States Environmental Protection Agency says producing stronger plants by grafting can reduce the need to use pesticides10.

Agriculture could not exist as we know it without grafting. Many fruits and nuts have been improved through this method. Some common fruit trees such as sweet cherries and McIntosh apples have to be grafted.

Bing cherries, for example, are one of the most popular kinds of cherries. But a Bing cherry tree is not grown from seed. Branches that produce Bing cherries must be grafted onto root stock. All sweet cherries on the market are grown this way.

And then there are seedless fruits like navel oranges and seedless watermelons. Have you ever wondered how farmers grow them? Through grafting.

The grapefruit tree is another plant that depends on grafting to reproduce. Grapes, apples, pears and also flowers can be improved through grafting.

In an age of high-technology agriculture, grafting still holds an important place.

And that's the VOA Special English Agriculture Report, written by Mario Ritter. You can learn more about agriculture, and download MP3 files and transcripts11 of our reports, at www.unsv.com.

graft : to unite (a shoot or bud) with a growing plant(嫁接)



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1 graft XQBzg     
n.移植,嫁接,艰苦工作,贪污;v.移植,嫁接
参考例句:
  • I am having a skin graft on my arm soon.我马上就要接受手臂的皮肤移植手术。
  • The minister became rich through graft.这位部长透过贪污受贿致富。
2 grafting 2e437ebeb7970afb284b2a656330c5a5     
嫁接法,移植法
参考例句:
  • Even grafting new blood vessels in place of the diseased coronary arteries has been tried. 甚至移植新血管代替不健康的冠状动脉的方法都已经试过。
  • Burns can often be cured by grafting on skin from another part of the same body. 烧伤常常可以用移植身体其它部位的皮肤来治愈。
3 remains 1kMzTy     
n.剩余物,残留物;遗体,遗迹
参考例句:
  • He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
  • The remains of the meal were fed to the dog.残羹剩饭喂狗了。
4 genetic PgIxp     
adj.遗传的,遗传学的
参考例句:
  • It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
  • Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
5 grafted adfa8973f8de58d9bd9c5b67221a3cfe     
移植( graft的过去式和过去分词 ); 嫁接; 使(思想、制度等)成为(…的一部份); 植根
参考例句:
  • No art can be grafted with success on another art. 没有哪种艺术能成功地嫁接到另一种艺术上。
  • Apples are easily grafted. 苹果树很容易嫁接。
6 scion DshyB     
n.嫩芽,子孙
参考例句:
  • A place is cut in the root stock to accept the scion.砧木上切开一个小口,来接受接穗。
  • Nabokov was the scion of an aristocratic family.纳博科夫是一个贵族家庭的阔少。
7 cleft awEzGG     
n.裂缝;adj.裂开的
参考例句:
  • I hid the message in a cleft in the rock.我把情报藏在石块的裂缝里。
  • He was cleft from his brother during the war.在战争期间,他与他的哥哥分离。
8 joint m3lx4     
adj.联合的,共同的;n.关节,接合处;v.连接,贴合
参考例句:
  • I had a bad fall,which put my shoulder out of joint.我重重地摔了一跤,肩膀脫臼了。
  • We wrote a letter in joint names.我们联名写了封信。
9 scions 2f5dd543d83d28564297e8138914f0a2     
n.接穗,幼枝( scion的名词复数 );(尤指富家)子孙
参考例句:
  • Eldritch giants are powerful scions of arcane lore. 邪术巨人是神秘奥术知识的强大传承者。 来自互联网
  • Grafting can join scions with desirable qualities to root stock that is strong and resistsand insects. 嫁接能够将理想质量的接穗嫁接到强有力抗病虫害的砧木上。 来自互联网
10 pesticides abb0488ed6905584ea91347395a890e8     
n.杀虫剂( pesticide的名词复数 );除害药物
参考例句:
  • vegetables grown without the use of pesticides 未用杀虫剂种植的蔬菜
  • There is a lot of concern over the amount of herbicides and pesticides used in farming. 人们对农业上灭草剂和杀虫剂的用量非常担忧。 来自《简明英汉词典》
11 transcripts 525c0b10bb61e5ddfdd47d7faa92db26     
n.抄本( transcript的名词复数 );转写本;文字本;副本
参考例句:
  • Like mRNA, both tRNA and rRNA are transcripts of chromosomal DNA. tRNA及rRNA同mRNA一样,都是染色体DNA的转录产物。 来自辞典例句
  • You can't take the transfer students'exam without your transcripts. 没有成绩证明书,你就不能参加转学考试。 来自辞典例句
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