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ID:13065880
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时间:2018-07-20
《农学园艺植保专业外语-山西农业大学》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
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
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