EXPLORATIONS - Working to Protect Plants for Future Generations
时间:2019-01-12 作者:英语课 分类:2012年VOA慢速英语(二)月
EXPLORATIONS - Working to Protect Plants for Future Generations
CHRISTOPHER CRUISE: I’m Chrisopher Cruise.
MARIO RITTER: And I’m Mario Ritter with EXPLORATIONS in VOA Special English. Today we tell about concerns about plant life, including agricultural crops. And we tell about efforts to keep them growing in the years to come.
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CHRISTOPHER CRUISE: Agricultural experts say crop diversity is important to feed the increasing population of our planet. They say having a large variety of plants also helps to protect against possible crop diseases and future crises.
Hundreds of thousands of different plants now exist. But many experts say the number has decreased sharply during the past century.
One of the world’s largest seed conservation projects has predicted further losses. The Millennium 2 Seed Bank Partnership 3 is warning that up to one hundred thousand plant species could permanently 4 disappear. The rich collection of genes 5 that decide their qualities would disappear with them.
MARIO RITTER: Many experts blame climate change and loss of habitat, normal growth area, for damaging plant life. They say human activities and poorly planned, overly heavy use of land also are responsible.
Paul Wallace of Petaluma Seed Bank looks at heirloom seeds. Many are traditional varieties passed down from generation to generation.
The United Nations Food and Agriculture Organization says modern business farming is responsible for loss of farmers’ traditional crop varieties. The “Green Revolution” of the twentieth century changed agriculture. Some experts say the use of modern commercial farming methods saved millions of people from starvation. Farmers planted, watered, and fertilized 6 their crops with the help of machines. They treated their fields with chemicals to control insects and diseases. Harvests grew larger and higher quality.
But another result was that some traditional crops were lost.
CHRISTOPHER CRUISE: The Food and Agriculture Organization says about two hundred fifty thousand plant species are now known to exist. The FAO notes that today, thirty thousand plant species could be eaten. Still, it says, only seven thousand have been used for food.
About one hundred twenty crops are grown to feed humans. The FAO says nine of those crops provide seventy five percent of human food. Rice, wheat and maize 7 are said to supply more than half of human food.
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MARIO RITTER: Not all experts agree that a decrease in cultivated food crops is a crisis. A recent study showed a different situation, at least in the United States. The study examined records of plant varieties in America during the past century.
The study was the project of Paul Heald of the University of Illinois College of Law and Susannah Chapman of the Anthropology 8 Department at the University of Georgia. They found that the total number of vegetable and apple crop varieties in the United States did not fall over the past century. Instead, Professor Heald says, the study may show a small increase in the number of varieties.
CHRISTOPHER CRUISE: Professor Heald and Ms. Chapman examined records of forty-two thousand vegetable crops. The crops were grown from nineteen three to two thousand four. They also studied apple variety records from nineteen hundred to two thousand.
Some scientists and others blame patenting for what they say are losses of crop diversity. But the study did not find that plant patents influenced the number of newly created plants. The researchers said they did not make a major change in the number.
A patent is the legal right of an inventor to a process or a product, even a plant. To get this right, the inventor has to demonstrate the qualities that make the patented plant different from other plants. The inventor must show that the plant has been reproduced asexually. This usually means that the plant is cut or its tissues have been connected to another plant.
MARIO RITTER: Asexual reproduction proves that the inventor can reproduce the plant. Grafting 9 is a way to produce plants from parts of existing plants instead of seeds, which cannot be used. Branches or buds are cut from one plant and placed on another plant.
American patent law says a new version of plant also can be discovered, but only on land used for growing. Wild plants in nature cannot be patented. They do not belong to any one owner.
CHRISTOPHER CRUISE: The two researchers looked at three dates when laws protecting the rights of patent holders 10 took effect. For example, seeds were first patented in nineteen seventy. The researchers say that, as they examined the records, they kept waiting for the number of new plant varieties to drop. But that did not happen. Instead, Mr. Heald says, they had a surprise.
PAUL HEALD: “We decided 11 there is, there is, something wrong here, something wrong with the conventional story.”
MARIO RITTER: Paul Heald says he thinks damage to the environment over the past century makes people believe that crop diversity also suffered.
PAUL HEALD: ”There is no doubt that the twentieth century was an environmental disaster. Our normal assumptions I think about almost all environmental issues is that the news is bad.”
Instead, he says, the development of new plant varieties is something to feel good about. The professor adds that new kinds of plants develop as a result of unofficial activities. He says immigrants, seed collectors, small farmers and local gardeners all keep and start new varieties.
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CHRISTOPHER CRUISE: Today, many individuals and groups worldwide are working to guarantee plant life for the future. One method for doing so is called “in situ”, meaning “in place.” In situ preservation 12 means a plant is grown in its normal environment. Another method is called “ex situ.” In ex situ, the plant is removed from its normal growing area and its seeds collected.
Shannon Carmody is with the Heritage Farm in Decorah, Iowa. There, workers grow and keep plants both ex situ, in seed collections, and in situ, on the farm’s three hundred sixty hectares.
MARIO RITTER: The grounds around Heritage Farms are hilly. Ms. Carmody says the hills help protect the plant life.
In her words, “We have these valleys, and then gardens on either side. They create a kind of natural barrier. The barrier lets us prevent cross-pollination 13 of all our different varieties that we preserve here.”
Cross-pollination means the movement of pollen 14 from one plant to another. If that happens, it could change the genetic 15 structure of the plants.
Heritage Farm saves material from plants that can be regenerated 16 -- grown again. Regeneration can be gained using seeds, bulbs or roots. The farm keeps seeds for heirloom and open-pollinated fruit and vegetable plants. Open pollination means pollination by wind, insects, birds and other natural methods.
The Heritage Farm collection does not include potatoes, which are not regenerated by seed.
CHRISTOPHER CRUISE: Experts differ about how to describe an “heirloom.” Each variety differs from others in its genes. Heirlooms are usually passed down over time from one family or gardening group to another. Some are hundreds of years old. Insects or the wind often open-pollinate heirlooms.
Some heirloom fruits and vegetables have names like Green Nutmeg Melon and Cowhorn Okra. Others are Black Beauty Eggplant, Blue Curled Scotch 17 Kale and Black Krimson Tomato.
At Heritage Farm or anywhere else, an heirloom garden in bloom promises a colorful sight.
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MARIO RITTER: Heritage Farm is the headquarters of Seed Savers Exchange, a not-for-profit group. It was established in nineteen seventy-five to save and share heirloom seeds. It also works to educate people about the need for genetic diversity.
Seed Savers Exchange has thousands of versions of different plant types. Its collection is one of the largest seed banks of its kind in North America.
Last year, Seed Savers Exchange donated two hundred seventy-one heirloom seed varieties to the Svalbard Global Seed Vault 18, far above Norway. The vault opened in February of two thousand eight. Since then, the exchange has stored one thousand six hundred sixty open-pollinated heirloom seed varieties in the storage center.
CHRISTOPHER CRUISE: Svalbard protects plant varieties against permanent loss from accidents, wars and natural disasters. Placing seeds in the vault also can prevent their loss through equipment failure or financial failures of gene 1 banks and plant museums.
The Norwegian government built the seed vault into the side of an icy mountain. The vault is kept at under minus eighteen and eight-tenths degrees Celsius 19. At that temperature, officials say, seeds can last many years even if cooling power is lost.
Svalbard can hold more than four million different seed samples. Each sample contains five hundred seeds. The seeds are backups, or copies, of the varieties stored by seed banks around the world.
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MARIO RITTER: This program was written by Jerilyn Watson. I’m Mario Ritter.
CHRISTOPHER CRUISE: And I’m Christopher.
- A single gene may have many effects.单一基因可能具有很多种效应。
- The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。
- The whole world was counting down to the new millennium.全世界都在倒计时迎接新千年的到来。
- We waited as the clock ticked away the last few seconds of the old millennium.我们静候着时钟滴答走过千年的最后几秒钟。
- The company has gone into partnership with Swiss Bank Corporation.这家公司已经和瑞士银行公司建立合作关系。
- Martin has taken him into general partnership in his company.马丁已让他成为公司的普通合伙人。
- The accident left him permanently scarred.那次事故给他留下了永久的伤疤。
- The ship is now permanently moored on the Thames in London.该船现在永久地停泊在伦敦泰晤士河边。
- 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
- The study of psychology has recently been widely cross-fertilized by new discoveries in genetics. 心理学研究最近从遗传学的新发现中受益匪浅。
- Flowers are often fertilized by bees as they gather nectar. 花常在蜜蜂采蜜时受粉。
- There's a field planted with maize behind the house.房子后面有一块玉米地。
- We can grow sorghum or maize on this plot.这块地可以种高粱或玉米。
- I believe he has started reading up anthropology.我相信他已开始深入研究人类学。
- Social anthropology is centrally concerned with the diversity of culture.社会人类学主要关于文化多样性。
- 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。
- Slaves were mercilessly ground down by slave holders. 奴隶受奴隶主的残酷压迫。
- It is recognition of compassion's part that leads the up-holders of capital punishment to accuse the abolitionists of sentimentality in being more sorry for the murderer than for his victim. 正是对怜悯的作用有了认识,才使得死刑的提倡者指控主张废除死刑的人感情用事,同情谋杀犯胜过同情受害者。
- This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
- There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。
- The police are responsible for the preservation of law and order.警察负责维持法律与秩序。
- The picture is in an excellent state of preservation.这幅画保存得极为完好。
- The flowers get pollination by insects.这些花通过昆虫授粉。
- Without sufficient pollination,the growth of the corn is stunted.没有得到充足的授粉,谷物的长势就会受阻。
- Hummingbirds have discovered that nectar and pollen are very nutritious.蜂鸟发现花蜜和花粉是很有营养的。
- He developed an allergy to pollen.他对花粉过敏。
- 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。
- They are regarded as being enveloped in regenerated gneisses. 它们被认为包围在再生的片麻岩之中。 来自辞典例句
- The party soon regenerated under her leadership. 该党在她的领导下很快焕然一新。 来自辞典例句
- Facts will eventually scotch these rumours.这种谣言在事实面前将不攻自破。
- Italy was full of fine views and virtually empty of Scotch whiskey.意大利多的是美景,真正缺的是苏格兰威士忌。
- The vault of this cathedral is very high.这座天主教堂的拱顶非常高。
- The old patrician was buried in the family vault.这位老贵族埋在家族的墓地里。