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1、Afernthathyperaccumulatesarsenic(这是题目，百度一下就能找到原文好，原文还有表格，我没有翻译)Ahardy,versatile,fast-growingplanthelpstoremovearsenicfromcontaminatedsoilsContaminationofsoilswitharsenic,whichisbothtoxicandcarcinogenic,iswidespread1.WehavediscoveredthatthefernPterisvitta
2、ta(brakefern)isextremelyefficientinextractingarsenicfromsoilsandtranslocatingitintoitsabove-groundbiomass.Thisplant—which,toourknowledge,isthefirstknownarsenichyperaccumulatoraswellasthefirstfernfoundtofunctionasahyperaccumulator—hasmanyattributesthatrec
3、ommenditforuseintheremediationofarsenic-contaminatedsoils.WefoundbrakeferngrowingonasiteinCentralFloridacontaminatedwithchromatedcopperarsenate(Fig.1a).Weanalysedthefrondsofplantsgrowingatthesitefortotalarsenicbygraphitefurnaceatomicabsorptionspectroscop
4、y.Of14plantspeciesstudied,onlybrakeferncontainedlargeamountsofarsenic(As;3,280–4,980p.p.m.).Wecollectedadditionalsamplesoftheplantandsoilfromthecontaminatedsite(18.8–1,603p.p.m.As)andfromanuncontaminatedsite(0.47–7.56p.p.m.As).Brakefernextractedarsenicef
5、ficientlyfromthesesoilsintoitsfronds:plantsgrowinginthecontaminatedsitecontained1,442–7,526p.p.m.Arsenicandthosefromtheuncontaminatedsitecontained11.8–64.0p.p.m.Thesevaluesaremuchhigherthanthosetypicalforplantsgrowinginnormalsoil,whichcontainlessthan3.6p
6、.p.m.ofarsenic3.Aswellasbeingtolerantofsoilscontainingasmuchas1,500p.p.m.arsenic,brakeferncantakeuplargeamountsofarsenicintoitsfrondsinashorttime(Table1).Arsenicconcentrationinfernfrondsgrowinginsoilspikedwith1,500p.p.m.Arsenicincreasedfrom29.4to15,861p.
7、p.m.intwoweeks.Furthermore,inthesameperiod,fernsgrowinginsoilcontainingjust6p.p.m.arsenicaccumulated755p.p.m.Ofarsenicintheirfronds,a126-foldenrichment.Arsenicconcentrationsinbrakefernrootswerelessthan303p.p.m.,whereasthoseinthefrondsreached7,234p.p.m.Ad
8、ditionof100p.p.m.Arsenicsignificantlystimulatedferngrowth,resultingina40%increaseinbiomasscomparedwiththecontrol(datanotshown).After20weeksofgrowth,theplantwasextractedusingasolutionof1:1methanol:watertospeciatearsenicwith
