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寄生之dodder种子
说一种有害植物吧dodder的种子到处传播的说是它能够好像有感觉一样能认到有tomato prefume的东西。。还有impatiens也和tomato有类似作用
考古 by syangg
寄生(F15) 注意题目有变（12.1）
Version 1: 一个说的是dodder, 第一段说的它是怎么把种子撒在植物的树干里，然后怎么缠住植物导致植物死亡的。二段说西红柿地因为它减产。发现西红柿有个什么吸引它的种子。（反正说它难解决）三段好像发现一个什么可以解决这个问题。问题有一个是dodder是怎么影响西红柿的。
Version 2: 前面的机经上提到过的，关于一种植物，寄生在其他植物上面，如果它萌发以后在一周内没有找到寄主，就会死掉。它们的寄生，给西红柿的种植带来很大损失。然后研究人员就研究是什么原因导致此植物在萌发的时候能发现西红柿秧子。首先他们用一块潮湿的空地，发现这种植物不为所动。然后就在地里放上五颜六色的东西（好像是这个吧，不是关键，没仔细看），这个植物还是不为所动。最后研究人员发现，这个植物似乎长了“鼻子”，它可以闻到西红柿样子的气味，他们把这个植物放到西红柿地旁边，它就被吸引过去了。研究人员继续研究，从西红柿的气味中发现了7种成分，其中有3种成分对此植物有吸引力。然后在小麦的气味中也发现了同样的成分，但是小麦还含有一种成分，可以阻止这个植物的寄生，所以就成为以后帮助西红柿秧子遏制此寄生植物的思路。
问题1是，以下那个是正确的：我选择的是：这个寄生植物如果一周找不到寄主就会死亡。问题2是，文章的主旨，我选择的是：介绍了一种新的方法吧（不好意思，这个记不清楚了。不敢误导，但是肯定是关于新的什么东东的）
问题3是，这个寄生植物是怎么影响西红柿的，我的选择是：ROB西红丝的水分
Version 3:一个说的是dodder, 第一段说的它是一定要在一个星期内找到寄主，不然会死。又说一般它的寄主最后都会死（有题，那个must be true,里面有个选项，dodder will eventually kill the plant）。它还引起了某年西红柿的收成损失xxx（一个数目或者比例）。第二段说作相关的研究，开始种在一片地方，放其他植物在旁边，它不会倍吸引过去。然后放放西红柿就倍吸引过去了。然后研究人员在西红柿研究出了7种香素，这些香素有几种在wheat中也有，但是wheat中还有一种抑制dodder的香素。最后一段我忘了说什么了。有一道题目是问第二段中说了些什么。选项中有个选项是出现在第一段的，一个说dodder需要在一个星期内找到寄主，不然会死去。正确的选项应该是wheat中有一种抑制dodder的香素。
Version 4:第一段:講一種植物(dodder)根很淺,因為他把所有的能量都拿來長他的shoot,然後要在一星期內找到寄生主因此影響農作物生長,最後一句話是,他會影響pomato的產量
第二段:科學家好像要嘗試找出為什麼dodder有這種特性,參考下文
At first, the researchers set various possible targets several centimeters from dodder sprouts. A pot of moist soil alone didn't attract the seedlings, nor did vials of dyed water that created colored light. But a pot with a young tomato plant, and even a cup of perfume made of tomato volatiles, did attract the seedlings
我記得最後一句是..... dodder grows toward impatiens and tomatoes, but not wheat.
Q:問整個第三段的功能(整個第三段反黃):有兩個選項很像A:針對前面講到的題出一個conclusion 另一個:.....findings 我好像選這個這題很不確定大家要在判斷一下
第三段:整段就在解釋為什麼wheat不會attract dodder,科學家分析tomato中有7種perfume其中有四種會吸引dodder,wheat也有其中一種,但是wheat也有一種東西會repel dodder,因此提供了一種可以防治dodder的想法
When researchers tested seven ingredients in the tomato perfume individually, three of them proved attractive to the dodder. One of those attractants showed up in wheat, but the wheat perfume also contained a substance that repelled the seedlings. Such a repellent might offer a new route for fighting dodder
Q:忘了題目講啥,ans好像是提供一種可以防治dodder的方法
参考文章：（我根据JJ里的信息稍微的关注了一下，供参考）
Scent Stalking: Parasitic vine grows toward tomato odor
Susan Milius
A wiry orange vine finds plants to raid for nutrients by growing toward their smell, researchers report.
One of the parasitic plants called dodders responds to volatile compounds wafting off nearby plants and shows preferences for certain species, says Consuelo De Moraes of Pennsylvania State University in University Park. They say that their new work marks the first time that anyone has shown that a plant will grow toward airborne chemicals from other plants.
The experiment finally identifies a cue—scent—that draws dodder to its victims, adds Mark C. Mescher, also of Penn State
.
The U.S. Department of Agriculture lists dodder among the country's 10 worst weeds. When a dodder seed sprouts, it doesn't grow roots. All its energy goes into a tendril that shoots out in search of plants to tap for water and nutrients. If it's going to survive, it must latch on to a victim within about a week. The vine grows into a spaghetti tangle and can attack multiple plants, stunting their growth but not killing them.
Of the 150 species of dodder, the researchers selected Cuscuta pentagona, says coauthor Justin Runyon, also of Penn State
. This species bedevils tomato growers in California, where it costs them an estimated $4 million a year in reduced yields.
De Moraes' team and other researchers have studied the volatile compounds released by plants that are mauled by caterpillars or other pests. In the new study, reported in the Sept. 29 Science, the team took a different point of view, looking at how an attacker, the dodder, takes advantage of volatiles to target its prey.
At first, the researchers set various possible targets several centimeters from dodder sprouts. A pot of moist soil alone didn't attract the seedlings, nor did vials of dyed water that created colored light.But a pot with a young tomato plant, and even a cup of perfume made of tomato volatiles, did attract the seedlings
To minimize any confounding cues, such as shading or light, the researchers then set the possible attractants in chambers connected to the plant by curving pipes. Again, the seedlings grew toward the scent.
Testing various victim species, the researchers found that dodder grows toward impatiens and tomatoes.Wheat won't sustain dodder well, and given a choice, parasite seedlings shunned it and grew toward tomatoes.
When researchers tested seven ingredients in the tomato perfume individually, three of them proved attractive to the dodder. One of those attractants showed up in wheat, but the wheat perfume also contained a substance that repelled the seedlings. Such a repellent might offer a new route for fighting dodder, Mescher speculates.
An insect ecologist who has also studied plant volatiles, Rick Karban of the University of California, Davis comments, "The significance of this [study] to me is that it indicates that without a central nervous system, plants are capable of behaving in ways that appear fairly sophisticated."
让考古来得更猛烈些吧！~ |
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发表于 2011-7-9 00:22:41
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