It is easy for us to tell who our family members are, but do plants recognize(識別) 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 or strangers.
When jewelweeds were planted in pots with strangers, the plants started to grow more leaves than if they had been planted alone. This response(反應(yīng))suggests that plants are competing with strangers for sunlight, since a plant with more leaves can receive more light and make more food. Jewelweeds usually grow in the shade, where sunlight is not enough.
When jewelweed seedlings(幼苗)were planted with siblings, they grew a few more branches than they usually 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 found 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 just 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.
【小題1】 What does the underlined word siblings mean?
A.Flowers come from foreign countries. |
B.Plants growing in different environments. |
C.Flowers planted with lots of strangers. |
D.Plants that are the same kind. |
A.make a comparison | B.introduce a topic |
C.describe a pretty flower | D.build a new theory |
A.grow more leaves than those planted in groups |
B.become taller than those with more branches |
C.grow fewer leaves than those planted with strangers |
D.become ill easily because they can’t get enough shade |
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 |
【小題1】D
【小題2】B
【小題3】C
【小題4】C
解析試題分析:這篇文章講的是科學(xué)家通過做實(shí)驗(yàn),發(fā)現(xiàn)將一種植物與不同種類的植物種植在一起,它會和其他植物競爭養(yǎng)分,將會長的更好,如果單獨(dú)種植的話,則會分享資源,而不競爭。
【小題1】推斷題。由第二段最后一句In their experiments, Murphy and Dudley planted jewelweeds in pots with either siblings or strangers.在他們的實(shí)驗(yàn)中,Murphy and Dudley將鳳仙花要么和同類植物種植在一起,要么和不同的植物種植在一起。由后面的詞義可推出siblings的意思是同類植物。故選D
【小題2】推斷題。從第一自然段Some do, scientists say, according to a report by Science News in early 2010.可知植物也能夠分辨出它的同類,第二自然段對這個說法進(jìn)行了一項(xiàng)有關(guān)jewelweeds鳳仙花的研究,所以在此是為了點(diǎn)明主題。
【小題3】細(xì)節(jié)題。由第三段第一句When jewelweeds were planted in pots with strangers, the plants started to grow more leaves than if they had been planted alone.當(dāng)把鳳仙花和不同種類的植物種植在一起時(shí),它就會比單獨(dú)種植時(shí)生長出更多的葉子。故可知,答案選C
【小題4】主旨題。這篇文章講的是科學(xué)家通過實(shí)驗(yàn),發(fā)現(xiàn)植物也可以辨別出哪些植物與自己是同一種類的。故選C.
考點(diǎn):科普類說明文
點(diǎn)評:本文較難,科技類的文體是比較繁瑣的,因?yàn)閷S忻~較多。學(xué)生在解答這類題目時(shí),首先對文章有大致的掌握,對于文章一遍沒有看懂時(shí),可以先看題目,按照文章題目的提示,再在文章中找出相對應(yīng)的地方,然后仔細(xì)分析文章的上下文,同時(shí)對于專有名詞可以用筆畫出,通過多個地方的比較就可以猜出意思了。
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