ResearchersfromtheUniversityof-查字典问答网

来自顾慧平的问题

　　ResearchersfromtheUniversityofHaifa-Oranimhavemanagedtomakeoutthe"self-irri-gating"mechanism(构造)ofthedesertrhubarbwhichenablesittoharvest16timestheamountofwaterthanotherwiseexpectedforaplantintheNegevDeser

　　 ThedesertrhubarbgrowsinthemountainsofIsrael'sNegevDesertwheretheaveragerainfallisparticularlylow(75mmperyear).Unlikemostoftheotherdesertplantspecieswhichhavesmallleavessoastoreducewaterlossthisplantisuniqueinthatitsleavesarepar?ticularlylarge.

　　 ProfessorSimchaLev-YadunProfessorGidiNe'emanandProfessorGadiKatzircameacrossthisuniqueplantwhilestudyingthefieldareaandnoticedthatitswaxyleavesareunusuallylarge.Theyobservedaridged(成脊状的)structureoneachleaf.

　　 Thescientistsexplainedthatthesedeepandwidedepressions(凹陷)intheleavescreatea"channeling"mountainlikesystembywhichtherainwaterischanneledtowardthegroundsur?roundingtheplant'sdeeproot.Otherdesertplantssimplyabsorbtherainwaterthatgoesthroughthegroundinitsimmediatesurroundings.

　　 Thefindingshaveshownthatthenaturalselectionprocesshasresultedintheevolutionofthisplant'sextremelylargeleaveswhichimproveditsabilitytosurviveinthearidclimateofthedesert.Theresultsofexperimentsandanalysisoftheplant'sgrowth―inanareawithanaverageannualrainfallof75 mm―showedthatthedesertrhubarbisabletoharvestquantitiesofwaterthatare16 timestheamountofwaterharvestedbythesmallleafedplantsoftheNegevDesert.WhentheresearchteamwateredthepJantartificiallytheyobservedhowthewaterflowsalongthecourseoftheleaves'depressionstothegroundsurroundingtheplant'ssinglerootandthengoesthroughthegroundtoadepthof10cmormore.Undertheexperimentalcondi?tionswatergoesthroughthegroundonlyasdeepas1cm."Weknowofnootherplantinthedesertsoftheworldthatfunctionsinthismanner"theresearchersconcluded.

　　( )1.Whatisthebesttitleforthispassage?

　　 A.HowPlants'"Selfirrigating"MechanismWorks

　　 B.HowPlantsGrowingintheDesertSurvive

　　 C.ADesertPlantGrowingintheNegevDeser