有毒植物~~~考古已确认！！！

sweetyecho

版本一   有害植物

V1 Bychenr523

阅读有一篇是说一种有害植物吧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tomatoprefume的东西。。还有impatiens也和tomato有类似作用

V2 by lixianzhen
第一段：一种植物叫dotter，不发展根部，一个劲儿的长小东西，这些小东西一个星期之内飞出去，会依附到别的植物上，对其造成毁灭性打击，美国的农民每年损失N多million。

第二段：科学家发现这货貌似有嗅觉，就做实验，把他放在几盆东西中间，有土豆（活），土豆（死），土豆液和小麦。发现这货确实会挑，死的那个上面一个小东西都没有，获得和液里有很多，小麦上有一些，不多

第三段：科学家们就研究为什么，后来分离出土豆液里的成分一个个分析，发现有几种能引起反应的成分。分离小麦的时候发现有吸引的还有排斥的，说这些排斥的能为防治这货提供一个新思路。（有题问这段的作用，我选的是为了说明研究的实际意义）

这是我做过的最简单的阅读，当时就觉得凄凉的不行。

V3 by sharian 760 q51v40
小寄生植物d的故事 (简单)
第一段说d怎么有害，它机制是什么，它危害了多少多少农业。
第二段说科学家发现可以用化学方式吸引d，说湿度没用，光也没用，但是味道有用。Impatien和tomato都吸引d，但wheat没有。
第三段说科学家就分离了各种香味拉，发现wheat不吸引的原因是因为它除了有吸引的香味之外还有排斥的，所以可能对控制d有重要意义。
问到主旨，类似选的是explanation
好像问到第一段里的一个细节
问到第三段（wheat）的功用，因为implication in 农业之类

V4 by epl6200l
2.1.3 有害植物(共三段,一屏不到)
第一段说明dodder为农民带量大量金额的损失
第二段是一个实验, 发现dodder会寄生在某些植物上, 如tomato和impatiens,某些种类的植物则不会
第三段发现wheat和tomato发出共同的气味, 但不寄生wheat, 所以可以利用这一点来帮助农民
考了(1)主旨题, (2)第三段的目的, (3)第二段的主旨: 我选的是说了dodder会选择某些植物寄生, 某些不会

版本二
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 fromdodder sprouts. A pot of moist soil alone didn't attract the seedlings, nor didvials of dyed water that created colored light. But a pot with a young tomatoplant, and even a cup of perfume made of tomato volatiles, did attract theseedlings
我記得最後一句是..... doddergrows 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 showedup in wheat, but the wheat perfume also contained a substance that repelled theseedlings. 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

背景文

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 towardtomato odor

Susan Milius
A wiry orange vine finds plants to raid fornutrients by growing toward their smell, researchers report.

One of the parasitic plants called dodders responds to volatile compounds waftingoff nearby plants and shows preferences for certain species, says Consuelo DeMoraes of Pennsylvania State University in University Park. They say that theirnew work marks the first time that anyone has shown that a plant will growtoward airborne chemicals from other plants.

The experiment finally identifies acue—scent—that draws dodder to its victims, adds Mark C. Mescher, also of Penn State
.
The U.S. Department of Agriculture lists dodderamong the country's 10 worst weeds. When a dodder seed sprouts, it doesn't growroots. All its energy goes into a tendril that shoots out in search of plantsto tap for water and nutrients.If it's going to survive, it must latch on toa victim within about a week. The vine grows into a spaghettitangle and can attack multiple plants, stunting their growth but not killingthem.

Of the 150 species of dodder, the researchersselected 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 havestudied the volatile compounds released by plants that are mauled bycaterpillars or other pests. In the new study, reported in the Sept. 29 Science, the team took adifferent point of view, looking at how an attacker, the dodder, takesadvantage of volatiles to target its prey.

At first, the researchers set various possible targets several centimetersfrom dodder sprouts. A pot of moist soil alone didn't attract the seedlings, nordid vials of dyed water that created colored light.But a pot with a youngtomato plant, and even a cup of perfume made of tomato volatiles, did attractthe seedlings

To minimize any confounding cues, such asshading or light, the researchers then set the possible attractants in chambersconnected to the plant by curving pipes. Again, the seedlings grew toward the scent.

Testing various victim species, the researchersfound that doddergrows toward impatiens and tomatoes.Wheat won't sustain dodder well, and givena choice, parasite seedlings shunned it and grew toward tomatoes.

When researchers tested seven ingredientsin the tomato perfume individually, three of them provedattractive to the dodder. One of those attractants showed up in wheat, but thewheat perfume also contained a substance that repelled the seedlings. Such arepellent might offer a new route for fighting dodder, Mescher speculates.

An insect ecologist who has also studiedplant volatiles, Rick Karban of the University of California, Davis comments,"The significance of this [study] to me is that it indicates that withouta central nervous system, plants are capable of behaving in ways that appearfairly sophisticated."

-大家说这篇非原文~不过可做作为背景文来看~

第一篇【大意就差不多了】

Dodder is a wiry, orange vine that steals water and nutrients fromother plants. Scientists have now found that this vine chooses its victim bysmell, growing its shoots in the direction of a plant's natural perfume. A seedlingof a vine known as dodder attaches to a tomato plant.When a dodder seed sprouts, itdoesn't grow roots to seek its own food. Instead, it grows a shoot that reachesout to other plants, tapping them for food. The baby vine needs to find a hostwithin a week to survive. It then grows into a spaghetti tangle that can evenensnare more than one plant.Also known as strangleweed andwitches' shoelaces, dodders are listed among the 10 worst weeds in the UnitedStates. They can cost farmers millions of dollars by stunting their crops.To figure out how a type ofdodder vine known to prefer tomato plants finds a victim, scientists placeddodder sprouts near several possible targets. These targets included pots ofmoist soil, little jars of dyed water that created colored lights, young tomatoplants, and even a cup of perfume made from chemicals that tomato plants giveoff.Seedlings grew toward the tomatoplant. They also reached out toward the cup of tomato perfume. They tended notto grow toward the moist soil or colored water.The scientists then used adifferent setup, hiding the targets in chambers connected to dodder sproutsonly by curving pipes, so the vine could find them only by smell. Doddersprouts still grew toward their favored targets.By placing dodder sprouts neardifferent plants, the scientists found that the type of dodder that they werestudying prefers tomatoes and a flower called impatiens. And when given achoice between tomato and wheat, vine seedlings grow toward tomato.The researchers then tested sevenof the ingredients that make up tomato perfume separately. Dodder sprouts wereattracted to three of them.One of these ingredients turns upin wheat perfume, but the wheat perfume also contains a substance that repelsdodder sprouts. This chemical could offer farmers one way to fight the vine andsave their crops.—C. Gramling

第二篇【据说原文比这简单点，实验内容什么的描述的很简单】

One ofthe parasitic plants called dodders responds to volatile compounds wafting offnearby plants and shows preferences for certain species, says Consuelo DeMoraes of Pennsylvania State University in University Park. They say that theirnew work marks the first time that anyone has shown that a plant will growtoward airborne chemicals from other plants.
The experiment finally identifies a cue—scent—that draws dodder to itsvictims, adds Mark C. Mescher, also of Penn State.
The U.S. Department of Agriculture lists dodder among the country's 10worst weeds. When a dodder seed sprouts, it doesn't grow roots. All its energygoes into a tendril that shoots out in search of plants to tap for water andnutrients. If it's going to survive, it must latch on to a victim within abouta 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 Cuscutapentagona, says coauthor Justin Runyon, also of Penn State. This speciesbedevils tomato growers in California, where it costs them an estimated $4million a year in reduced yields.
De Moraes' team and other researchers have studied the volatilecompounds released by plants that are mauled by caterpillars or other pests. Inthe new study, reported in the Sept. 29 Science, the team took a differentpoint of view, looking at how an attacker, the dodder, takes advantage ofvolatiles to target its prey.
At first, the researchers set various possible targets severalcentimeters from dodder sprouts. A pot of moist soil alone didn't attract theseedlings, nor did vials of dyed water that created colored light. But a potwith a young tomato plant, and even a cup of perfume made of tomato volatiles,did attract the seedlings (see movie athttp://www.sciencenews.org/articles/20060930/tomato.mov).
To minimize any confounding cues, such as shading or light, theresearchers then set the possible attractants in chambers connected to theplant by curving pipes. Again, the seedlings grew toward the scent.
Testing various victim species, the researchers found that dodder growstoward impatiens and tomatoes. Wheat won't sustain dodder well, and given achoice, parasite seedlings shunned it and grew toward tomatoes.
When researchers tested seven ingredients in the tomato perfumeindividually, three of them proved attractive to the dodder. One of thoseattractants showed up in wheat, but the wheat perfume also contained asubstance that repelled the seedlings. Such a repellent might offer a new routefor fighting dodder, Mescher speculates.
An insect ecologist who has also studied plant volatiles, Rick Karbanof 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."