托福阅读真题解析.docx
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托福阅读真题解析.docx
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托福阅读真题解析
2013年1月12日托福阅读真题解析
第一篇植物开花与日照的关系
【机经回忆】
什么因素影响花期
植物通过感受不同光照事件长短,决定播种,科学家通过对叶子遮光处理,分为三种:
不受光影响,长日照和短日照,检测植物的信号。
但是最后还是没有收获,但是日照长短对植物的影响是明显的
【重点词汇解析】
sunlight日光
long-day长日照
shortday短日照
plant植物
seed种子
signal信号
obvious明显的
【机经解析】
光照长短对植物生长的影响
Lightdurationorphotoperiodreferstotheamountoftimethataplantisexposedtosunlight.Whentheconceptofphotoperiodwasfirstrecognizeditwasthoughtthatthelengthofperiodsoflighttriggeredflowering.Thevariouscategoriesofresponsewerenamedaccordingtothelightlength(i.e.,short-dayandlong-day).Itwasthendiscoveredthatitisnotthelengthofthelightperiodbutthelengthofuninterrupteddarkperiodsthatiscriticaltofloraldevelopment.Theabilityofmanyplantstofloweriscontrolledbyphotoperiod.
Plantscanbeclassifiedintothreecategories,dependingupontheirfloweringresponsetothedurationofdarkness.Theseareshort-day,long-day,orday-neutralplants.Short-day,(longnights)plantsformtheirflowersonlywhenthedaylengthislessthanabout12hoursinduration.Short-dayplantsincludemanyspringandfallfloweringplantssuchaschrysanthemumandpoinsettia.Long-day,(shortnights)plantsformflowersonlywhendaylengthsexceed12hours.Theyincludealmostallofthesummer-floweringplants,aswellasmanyvegetablesincludingbeet,radish,lettuce,spinach,andpotato.Day-neutralplantsformflowersregardlessofdaylength.Someplantsdonotreallyfitintoanycategorybutmayberesponsivetocombinationsofdaylengths.Thepetuniawillflowerregardlessofdaylength,butflowersearlierandmoreprofuselyunderlongdaylight.Sincechrysanthemumsflowerundertheshort-dayconditionsofspringorfallthemethodformanipulatingtheplantintoexperiencingshortdaysisverysimple.Iflongdaysarepredominant,ablackplasticsheetisdrawnoverthechrysanthemumfor12hoursdailytoblockoutlightuntilflowerbudsareinitiated.Tobringalong-dayplantintoflowerwhensunlightisnotpresentlongerthan12hoursartificiallightisaddeduntilflowerbudsareinitiated.
LightDuration
Lightdurationreferstotheamountoftimethataplantisexposedtosunlight.TravelerstoAlaskaoftenmarvelatthegiantvegetablesandflowersthatgrowunderthelongdaysofthearcticsunevenwithcooltemperatures
Whenstartingtransplantsindoors,generallygiveplants12to14hoursoflightperday.Plantaregenerallyintolerantofcontinuouslightfor24hours
Photoperiod
Thefloweringresponseofmanyplantsiscontrolledbythephotoperiod(thelengthofuninterrupteddarkness).Photoperiodresponsecanbedividedintothreetypes.
Shortdayplantsflowerinresponsetolongperiodsofnightdarkness.Examplesincludepoinsettias,Christmascactus,chrysanthemums,andsingle-cropstrawberrie
Longdayplantsflowerinresponsetoshortperiodsofnightdarkness.Examplesincludeonionsandspinach
Dayneutralplantsflowerwithoutregardtothelengthofthenight,buttypicallyflowerearlierandmoreprofuselyunderlongdaylightregimes.Dayneutralstrawberriesprovidesummerlongharvesting(exceptduringheatextremes)
光照长短对花期的形成和长短的影响
BougainvilleaplantswereexposedtoartificiallyreducedlightintensitytocapturedifferentPhotosyntheticPhotonFluxDensity(PPFD),0%(directsunlight),30,50and75%shadingandtoobservetheeffectsofshadingonflowerformationandlongevity,leafchlorophyllandsugarcontentandqualityofplants.Plantattainedthegreatestleafsizewithmaximumbranchingwhenseedlingsweregrownin30and50%shading,whereas0%shadingshowedthelowestvalue.Growthparametersrelatedtotheplantcharacteristicssuchasbranchinitiation,branchgrowthandpotassiumcontentincreasedunderhighshadingtreatments.Plantsexposedto0%shadeshowedthehighestsugarcontentandthesugarcontentdecreasedbyincreasingshading.Thelowlightintensitythatresultsindecreasedsugarandchlorophyllcontentsmaybeattributedtothereductionofflowerinitiationandinturntotheaccelerationofflowerabscission.Inaddition,morethan30%shadingledtostopupflowerinitiationcompletely.Hence,itissuggestedthat0%shadingcanbeappliedtomaintainfrequentflowerinitiationandflowerlongevity.
第二篇英国农业的发展
【机经回忆】
这篇阅读讲英国农业如何在欧洲其他各国的农业**之前独自发展至小康水平。
。
。
英格兰的农业比欧洲其他国家发展的都早都好,其他国家在大战或者有瘟疫的时候英格兰都没受太大影响。
还说英格兰农场主发现农业获利很大后,就采取了高产的农产品,新技术,把原来tenure的农民都化成了签约式的,而且签约前要交钱否则就用别人(此处有题,大概是说四个选项里哪个没有在文中提到)。
还说到由于农场主采用了嫡长子继承制,所以没有土地仍然很集中。
还举例如提高房租,改善耕种方式,还有开始做羊毛,并且出口至欧洲各国甚至美国。
【重点词汇解析】
agriculture农业
European欧洲的
England英格兰
development发展
plague瘟疫
farm农场
benefit利益
newtechnology新技术
tenure终身职位;任期;保有
farmer农场主
thelinealprimogeniture[,pra?
mo'd?
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n?
t?
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]system嫡长子继承制
raisetherent提高房租
improvethecultivat
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