Jewelweeds, or Impatiens, are pretty flowers that grow in wet, shady places all over the Northern Hemisphere. According to a recent experiment, they seem to know their own flower family. www..com The 题目和参考答案——青夏教育精英家教网—

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Jewelweeds, or Impatiens, are pretty flowers that grow in wet, shady(多荫的) places all over the Northern Hemisphere. According to a recent experiment, they seem to know their own flower family. www..com

The experiment suggests that these flowers can know each other—or at least, know whether or not they came from the same mother plant. Together with other experiments, these results show that if the plants are able to know their siblings (兄弟姐妹), it’s not through their leaves, it’s through the roots.

Guillermo P. Murphy and Susan Dudley are a pair of botanists, or scientists who study plants, from McMaster University in Hamilton, Canada. In this experiment, they planted jewelweeds in pots (罐) with either siblings or strangers. Sibling plants were grown from seeds that came from the same mother plant. Stranger plants were grown from seeds from different plants.

If people were plants, then this experiment would be like showing that a person behaves differently if he grows up next to his brother than if he grows up next to a stranger.

When jewelweeds were planted in pots with strangers, the plants started to grow more leaves than if they had been planted alone. This response（反应）suggests that plants are competing with strangers for sunlight, since a plant with more leaves can receive more light—and make more food. Impatiens normally grow in the shade, where there is not enough sunlight.

When jewelweed seedlings were planted with siblings, they grew a few more branches than they normally would if they were alone — but they did not start growing lots of extra leaves. This behavior suggests the plants are more likely to share resources（资源）, rather than compete.

64. What is the main idea of the article?

A. Jewelweeds seem to know their own family. B. Jewelweeds love their siblings.

C. Jewelweeds share resources with others D. Jewelweeds grow in wet shady places

65. A plant with more leaves __________.

A. are likely to share more resources B. receive more competition

C. are likely to make more food D. hardly receive enough sunlight

66. From the passage, we learn that __________.

A. the flowers grow extra leaves when planted alone

B. the flowers know their siblings through their roots

C. the flowers can make friends with stranger plants

D. the flowers grow more branches when planted with strangers

ACB

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相关题目

Jewelweeds are pretty flowers that grow in wet, shady spots all over the Northern Hemisphere. According to a recent experiment, they seem to know their own flower family —or at least, recognize whether or not they came from the same mother plant. Together with other through their leaves, but through their roots.
Scientists planted jewelweeds in pots with either siblings（兄弟姐妹）or strangers. Sibling plants were grown from seeds that came from the same mother plant. Stranger plants were grown from seeds from different plants.
When jewelweeds were planted in pots with strangers, the plants started to grow more leaves than if they had been planted alone. This response suggests that plants are competing with strangers for sunlight, since a plant with more leaves can receive more light and make more food.
When jewelweed seedlings were planted with siblings, they few a few more branches than they normally would if they were alone—but they did not start growing lots of extra leaves. This behavior suggests the plants are more likely to share resources, rather than compete.
The plants only responded this way when they shared soil. If stranger seedlings were planted in different pots and placed next to each other, for example, they did not grow more leaves. This different shows that the plants must use their roots to detect sibling plants in the same soil. In 2007, Dudley and her team studied the Great Lakes sea rocket, a plant that grows on the beach—where it may be hard to get fresh water. In that experiment, the botanists observed that when sea rockets were planed with siblings, they tolerated each other. But when they were planted with strangers, the sea prickets reacted by working extra hard to grow lots of roots, but not extra leaves.
The different types of plants may react in different ways, but they have one thing in common: the roots. In both experiments, on Jewelweeds and sea rockets, the key was the shared soil—and other plant species may turn out to show similar behavior. These experiments, as well as earlier experiments, suggest “The phenomenon is quite common.” Says Hans de Kroonof, an ecologist in the Netherlands.
57．In Paragraph 1, the author mentions a recent experiment of Jewelweeds to___________.
A．make a comparison B．introduce a topic
C．describe a pretty flower   D．put forward a new theory
58．What can we know from the experiments done by scientists?
A．Jewelweeds can grow in the Northern Hemisphere.
B．Jewelweeds can grow in wet, shady spots.
C．Jewelweeds are more friendly to their siblings than to stranger plants.
D．jewelweeds can recognize their siblings through leaves.
59．If jewelweeds and their siblings are planted in different pots and placed close to one another, they will___________.
A．start to grow more leaves       B．detect the strangers
C．compete with sibling plants     D．grow normally
60．The best title of the passage would be___________.
A．Flower family knows its roots
B．The growing conditions of Jewelweeds
C．Jewelweeds and sea rockets
D．The stranger plant recognize each other

Scientists planted jewelweeds in pots with either siblings（兄弟姐妹）or strangers. Sibling plants were grown from seeds that came from the same mother plant. Stranger plants were grown from seeds from different plants.

When jewelweeds were planted in pots with strangers, the plants started to grow more leaves than if they had been planted alone. This response suggests that plants are competing with strangers for sunlight, since a plant with more leaves can receive more light and make more food.

When jewelweed seedlings were planted with siblings, they few a few more branches than they normally would if they were alone—but they did not start growing lots of extra leaves. This behavior suggests the plants are more likely to share resources, rather than compete.

The plants only responded this way when they shared soil. If stranger seedlings were planted in different pots and placed next to each other, for example, they did not grow more leaves. This different shows that the plants must use their roots to detect sibling plants in the same soil. In 2007, Dudley and her team studied the Great Lakes sea rocket, a plant that grows on the beach—where it may be hard to get fresh water. In that experiment, the botanists observed that when sea rockets were planed with siblings, they tolerated each other. But when they were planted with strangers, the sea prickets reacted by working extra hard to grow lots of roots, but not extra leaves.

The different types of plants may react in different ways, but they have one thing in common: the roots. In both experiments, on Jewelweeds and sea rockets, the key was the shared soil—and other plant species may turn out to show similar behavior. These experiments, as well as earlier experiments, suggest “The phenomenon is quite common.” Says Hans de Kroonof, an ecologist in the Netherlands.

57．In Paragraph 1, the author mentions a recent experiment of Jewelweeds to___________.

A．make a comparison B．introduce a topic

C．describe a pretty flower D．put forward a new theory

58．What can we know from the experiments done by scientists?

A．Jewelweeds can grow in the Northern Hemisphere.

B．Jewelweeds can grow in wet, shady spots.

C．Jewelweeds are more friendly to their siblings than to stranger plants.

D．jewelweeds can recognize their siblings through leaves.

59．If jewelweeds and their siblings are planted in different pots and placed close to one another, they will___________.

A．start to grow more leaves B．detect the strangers

C．compete with sibling plants D．grow normally

60．The best title of the passage would be___________.

A．Flower family knows its roots

B．The growing conditions of Jewelweeds

C．Jewelweeds and sea rockets

D．The stranger plant recognize each other

It is easy for us to tell who our family members are, but do plants recognize their own family? Some do, scientists say, according to a report by Science News in early 2010.

Guillermo P. Murphy and Susan Dudley are two plant scientists from McMaster University in Hamilton, Canada. They did a few experiments with Jewelweeds, a kind of flower that grows in wet, shady spots. They found that the flowers seem to know their own flower family. In their experiments, Murphy and Dudley planted jewelweeds in pots with either siblings (同属) or strangers.

When jewelweed seedlings were planted with siblings, they grew a few more branches than they normally would if they were alone – but they did not start growing lots of extra leaves. This behavior suggests the plants are more likely to share resources, rather than compete.

According to the Science News report, Jewelweeds are not the first plants that plant scientists have studied for family recognition. In 2007, Dudley and her team studied the Great Lakes sea rocket, a plant that grows on the beach – where it may be hard to get fresh water. In that experiment, the scientists observed that when sea rockets were planted with siblings, they tolerated each other. But when they were planted with strangers, the sea rockets reacted by working extra hard to grow lots of roots.

Dudley says this behavior makes sense because sea rockets, on the beach, get plenty of sun but struggle for water – so when they’re threatened, they compete for water. Jewelweeds have plenty of water but have to compete for sunshine, so they grow more leaves.

52. When the McMaster University scientists experimented with Jewelweeds, they __________.

A. planted Jewelweeds alone

B. separated jewelweeds from their siblings

C. planted Jewelweeds in an unusual environment

D. grew jewelweeds together with either family or strangers

53. Which of the following shows that Jewelweeds compete with others?

A. Jewelweeds grow extra leaves.

B. Jewelweeds grow more branches as well as extra leaves.

C. Jewelweeds grow more branches rather than more leaves.

D. Jewelweeds grow taller than usual.

54. The underlined word “scarce” in paragraph 3 means _____________.

A. dark B. not enough C. not available D. mild

55. From the text, we can conclude that the Great Lakes sea rockets ____________.

A. prove the same point as Jewelweeds B. compete with strangers for sunlight

C. cannot recognize their siblings D. grow more leaves when planted with strangers

56. What is the article mainly about?

A. New discoveries about plants. B. How plants compete with each other.

C. Family recognition among plants. D. Jewelweeds and the Great Lakes sea rockets.

57．In Paragraph 1, the author mentions a recent experiment of Jewelweeds to .