托福阅读真题解析Word文档下载推荐.docx

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　　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

　　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。

　　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?

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　　raisetherent提高房租

　　improvethecultivat