世界上最大的植物
刘立军 供稿
TRANSCRIPT
Scientists have discovered the world’s largest plant ― a seagrass meadow that has grown by repeatedly copying, or cloning, itself.
A genetic study found that the underwater field of green seagrass that lives off Australia’s western coast is a single organism. The organism, 180 square kilometers in size, has survived by making copies of itself for over 4,500 years.
The research was published in Proceedings of the Royal Society B.
The University of Western Australia’s Jane Edgeloe helped write the study. She wrote that the researchers confirmed that the meadow was a single organism. They did this by sampling and comparing the DNA of small pieces of seagrass from across the sea.
Several plants and animals can reproduce without sex. Researchers wrote that the process can create very fast growth. But clones of a single organism can be at increased risk of disease.
The scientists call the meadow of Poseidon’s ribbon weed “the most widespread known clone on Earth.”
“Widespread” is a term that means common over a wide area.
Although the seagrass meadow is very large, it faces risks. Ten years ago, the seagrass covered an area of around 18 square kilometers more than it does today. But storms and rising ocean temperatures linked to climate change have recently killed almost one tenth of the ancient seagrass bed.
I’m John Russell.
VOCABULARY
1. meadow n. a field covered in grass, used especially for hay 草地。例如：water meadows 岸边的草地
2. clone v. to produce an exact copy of an animal or a plant from its cells 以无性繁殖技术复制；克隆
3. organism n. a system consisting of parts that depend on each other 有机组织；有机体系
QUESTIONS
Read the statements. Then listen to the news and decide whether the statements are true (T) or false (F). Then correct the false statements.
1. Scientists have discovered the world’s second largest plant in Australia, which is a seagrass meadow that has grown by repeatedly copying itself.
2. Researchers did this study by sampling and comparing the DNA of small pieces of seagrass from across the sea.
3. This study shows that several plants and animals can reproduce without sex.
4. Researchers point out that clones of a single organism can be at increased risk of disease.
5. Although the seagrass meadow is very large, it doesn’t face risks.
6. Storms and rising ocean temperatures linked to volcano eruption have recently killed almost one tenth of the ancient seagrass bed.
KEY
Read the statements. Then listen to the news and decide whether the statements are true (T) or false (F). Then correct the false statements.
(F) 1. Scientists have discovered the world’s second largest plant in Australia, which is a seagrass meadow that has grown by repeatedly copying itself. （正确表达）Scientists have discovered the world’s largest plant in Australia, which is a seagrass meadow that has grown by repeatedly copying itself.
(T) 2. Researchers did this study by sampling and comparing the DNA of small pieces of seagrass from across the sea.
(T) 3. This study shows that several plants and animals can reproduce without sex.
(T) 4. Researchers point out that clones of a single organism can be at increased risk of disease.
(F) 5. Although the seagrass meadow is very large, it doesn’t face risks. （正确表达）Although the seagrass meadow is very large, it faces risks.
(F) 6. Storms and rising ocean temperatures linked to volcano eruption have recently killed almost one tenth of the ancient seagrass bed. （正确表达）Storms and rising ocean temperatures linked to climate change have recently killed almost one tenth of the ancient seagrass bed.
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