VOA标准英语2014--科学家发现蒲公英或能代替橡胶树

 

Rubber May Soon Come From Dandelions

Synthetic¹ rubber has been around for more than a century, but quality tires for cars, trucks and aircraft still need up to 40 percent or more natural rubber content.  As the source of natural rubber, the rubber tree, is prone² to disease and can be affected³ by bad weather.  So scientists are looking for replacements⁴ may have found one in a ubiquitous weed.

Rubber trees, growing mostly on Southeast Asian plantations⁵, are sensitive plants - giving the optimal⁶ yield of raw rubber only under ideal atmospheric⁷ conditions, an equal distribution of rainfall and bright sunshine, with the absence of strong winds.

They are also extremely sensitive to a plant disease that has devastated⁸ rubber plantations in the tree’s original habitat, South America.

Dandelions, on the other hand, are tough weeds, that grow, even in poor soil, and are not overly sensitive to a changing climate.

Scientists have long known that the dandelion's milky⁹ sap contains latex, the main ingredient of raw rubber.  A variety native to Kazakhstan is the richest source.

Researchers at Germany’s Fraunhofer Institute for Molecular¹⁰ Biology and Applied¹¹ Ecology, supported by car tire industry, are trying to manipulate its genes¹² to produce latex in quantities suitable for commercial exploitation, says lead researcher Dirk Pruefer.

“One of the main challenges in dandelion research was to produce plants, novel plants that have an improved rubber content that has a good economic behavior in the field.  And that is why we're working since years [for] years on the breeding program to develop new traits in the plants, stabilized¹³ traits - for example stable rubber content," said Pruefer.

The genetically-engineered dandelion is already producing half a ton of rubber per hectare, but Pruefer says the scientists’ goal is about twice as much.  They would also like to grow taller plants with upright leaves, which are more suitable for machine harvesting.

Pruefer says one of the leading tire manufacturers, Continental¹⁴ AG, is already testing tires made with dandelion-based rubber.

“They made a lot of testing tissues so see the quality of the material.  And what you can see is that the quality is similar to that what they have originally done with the rubber from the rubber tree," he said.

Researchers say large fields in Europe and Asia, currently unusable due to poor soil, may someday be covered with rubber-producing yellow flowers.

1 synthetic   

adj.合成的，人工的；综合的；n.人工制品

参考例句：

• We felt the salesman's synthetic friendliness.我们感觉到那位销售员的虚情假意。
• It's a synthetic diamond.这是人造钻石。

2 prone   

adj.(to)易于…的，很可能…的；俯卧的

参考例句：

• Some people are prone to jump to hasty conclusions.有些人往往作出轻率的结论。
• He is prone to lose his temper when people disagree with him.人家一不同意他的意见,他就发脾气。

3 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

4 replacements   

n.代替( replacement的名词复数 )；替换的人[物]；替代品；归还

参考例句：

• They infiltrated behind the lines so as to annoy the emery replacements. 他们渗透敌后以便骚扰敌军的调度。 来自辞典例句
• For oil replacements, cheap suddenly looks less of a problem. 对于石油的替代品来说，价格变得无足轻重了。 来自互联网

5 plantations   

n.种植园，大农场( plantation的名词复数 )

参考例句：

• Soon great plantations, supported by slave labor, made some families very wealthy. 不久之后出现了依靠奴隶劳动的大庄园，使一些家庭成了富豪。 来自英汉非文学 - 政府文件
• Winterborne's contract was completed, and the plantations were deserted. 维恩特波恩的合同完成后，那片林地变得荒废了。 来自辞典例句

6 optimal   

adj.最适宜的；最理想的；最令人满意的

参考例句：

• What is the optimal mix of private and public property rights in natural resources?私人和国家的自然资源产权的最适宜的组合是什么？
• Optimal path planning is a key link for the sailing contest.帆船最优行驶路径规划是帆船比赛取胜的关键环节。

7 atmospheric   

adj.大气的，空气的；大气层的；大气所引起的

参考例句：

• Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
• Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

8 devastated   

v.彻底破坏( devastate的过去式和过去分词)；摧毁；毁灭；在感情上（精神上、财务上等）压垮adj.毁坏的；极为震惊的

参考例句：

• The bomb devastated much of the old part of the city. 这颗炸弹炸毁了旧城的一大片地方。
• His family is absolutely devastated. 他的一家感到极为震惊。

9 milky   

adj.牛奶的，多奶的；乳白色的

参考例句：

• Alexander always has milky coffee at lunchtime.亚历山大总是在午餐时喝掺奶的咖啡。
• I like a hot milky drink at bedtime.我喜欢睡前喝杯热奶饮料。

10 molecular   

adj.分子的；克分子的

参考例句：

• The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
• For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时，分子的碰撞就停止了。

11 applied   

adj.应用的；v.应用，适用

参考例句：

• She plans to take a course in applied linguistics.她打算学习应用语言学课程。
• This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。

12 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

13 stabilized   

v.（使）稳定， （使）稳固( stabilize的过去式和过去分词 )

参考例句：

• The patient's condition stabilized. 患者的病情稳定下来。
• His blood pressure has stabilized. 他的血压已经稳定下来了。 来自《现代英汉综合大词典》

14 continental   

adj.大陆的，大陆性的，欧洲大陆的

参考例句：

• A continental climate is different from an insular one.大陆性气候不同于岛屿气候。
• The most ancient parts of the continental crust are 4000 million years old.大陆地壳最古老的部分有40亿年历史。