农学园艺植保专业外语-山西农业大学

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1、1ThePartsofAPlantandTheirFunctionsAplantisalivingorganism.Itismadeupofdifferentparts,eachofwhichhasaparticularpurpose,orspecializedfunction.Ifonepartoftheplantisnotfunctioningproperlythewholeplantwillsuffer.Butwemaycutflowersofftheplantorprunetheroots.Su

2、chdamageisonlytemporaryandsotheplantwillcontinuetogrow.Studythefollowingstatementscarefullyandwritedownwhethertheyaretrueornottrueaccordingtotheinformationexpressedabove.(a)Differentpartsofaplanthavespecializedfunctions.(b)Notallpartsofaplantneedfunction

3、properly.(c)Ifwecutflowersoffaplant,thewholeplantwillsuffer.Thebasicpartsofaplantaretherootsystem,whichisbelowtheground,andtheshootsystemabove.Therootofaplanthastwomainfunctions.Ittakesin,orabsorbs,waterandmineralsfromthesoilthroughtheroothairs,whichares

4、inglecellsnearthetipofeachroot.Theothermainfunctionoftherootistohold,oranchor,theplantfirmlyinpositioninthesoil.(d)Theshootsystemoftheplantisbelowtheground.(e)Waterandmineralsareabsorbedthroughtheroothairs.(f)Theplantisanchoredinthesoilbytherootsystem.Pl

5、antsuchassugarbeetandcarrotsareabletostorefoodintheirroots.Inthiswaytheycankeepgrowingformorethanoneseason.Inaddition,plantssuchascloverandlucerne,knownas‘legumes’,havespecialbacteriawhichliveontheroots.Thissimpleformsoflifetakenitrogenoutoftheairwhichis

6、inthesoil.Suchleguminousplantsareusuallyploughedunderthesoil.Bydoingthisthesoilismademorefertile.(g)Carrotscankeepgrowingformorethanoneseason.(h)Specialbacterialiveontherootsofallplants.(i)Thesoilismadefertilebyploughingcloverandlucerneunderthesoil.Thesh

7、ootsystemabovethegroundconsistsofthestem,theleaves,flowersandfruit.Oneofthefunctionsofthestemistosupporttheplant.Anotherimportantfunctionistoenablewaterandmineralstopassupfromtherootstotheleavesandflowers.Organicmaterialssuchassugartraveldownthestemtothe

8、roots.Theleavesgrowoutofthesideofthestem.Theirmainjobistomakefoodfortheplantbytheprocessknownasphotosynthesis.Forthisprocesssunlightisnecessary.Waterfromthesoilandcarbondioxidefromtheairareconvertedintosugarsandothercarboh