The damage of heavy metal to growth and development of rice(Oryza sativa L.)and wheat(Triticum aestivum L.)and The related molecular mechanisms were studiedfrom 1999 to 2002 Yangzhou with the polyacrylamide conncentration gradient gelwlectrophoresis technique,radioisotope trace kineic technique,HPLC technique,molecular biological technique and other physiologlcal measurement methods.Thetolerance mechanisms of rice and wheat to heavy metal stress was also analysed. 1 damages Rice and wheat were very sensitive to Cu~2+,Cd~2-,Hg~2+ stress at seedgernunatlon and seedï¼lug morphogenesls stagCs.me seed gernUnating percem旧驴decreased n the form of exponential decay with the CuZ",CdZ",HgZ"concentrationincreasing.he root elongation andthetlller aPPearance were slå³ificantly讪bitedby Cll'",Cd'",Hg".D**g。CtiVe VegCtatiVC gfOWth。lid gfs* ill*g peflod,thesensitivity ofrice and wheat to CuZ",CdZ",HgZ"stress decreased obviously. Compared wun other orpans,the growth and devefopment of roots mostsignificå’–ly nhibited by Cu'",C矿",Hg'".The nhibition on tiller aPPearance册salso slgIUgIUfica血.here was a slgmgmfic用血 negative linear relationship be阿化en tillernmber and CuZ",CdZ",Hg"concemation.he nhlbltlon on stem elongation,leafeXpansion and grain deve…mQè¡€ was low As yield coå‘·onents,low concentration Cu'",Cd'",Hg"mainly nhAnted theformation of effective ears of nce and Wheat,high conemiration Cf",Cd'",Hg'"resulted n less gfams per panlcles and lower 000ï¼grain weigh. rmong differsè¡€ heawmå’–Is,the order ofCuZ",CdZ",HgZ"Mibitiondegree onseen gennmatlon,root growth and tiller ppearance of nce and root grotvill of wheatwas CuZ">Cd'+>Hg'",Whil on leafandtiller ppearance ofwheat was Cd'"oHg">CuZ". 2 Molecular mecban'sin ofdamage hephotosy讪etlc rate ofnce and wheatWs significamlyhå±±bitedby CuZ",Cd'",Hgï½ St爬SS.Cf",C扩",Hg'"C。used the Cå’–eè¡€S Of photOSystem 11,photosystem,llgh harvesting plgnentTrotein complex and chlorophyll to decreasegfeatlyg and also wed the ratio of chlofophyll aï¼b,Which resulted in directnhibition on photosç¿esis.Cu2+,Cd'",Hg'"also disturbed the eXportaion ofphotosynthates from leaves and inhibited importation ofphotosynthates to sink o4ans.It was worth noting that the transformation ewen staä»° and sllgar,s nhibited byCJ",Cd",Hg'".Conseqç ’ntlx Så§ar acem"lated n the ieWes,Which "ugh nducea downï¼n唱"lation of Calivn cycle,therefore,photosyllthetlc rate sic。d do。 he effect of heaVy metals on respration indicated that the respiratory rate n theleWes and roots of nce册s e讪anced by the low concent例ion of CJ",Cd'",Hg'",bå nib庇dåŠ thehighconcelltratlon·Besides causing structml damagestoresPiratory aPParatUS,the inhibiting resPiration mechanism of CuZï¼¼ Cd",Hg》included:â‘ å•Šlase actvity andsoZyIYles eXpression was inhibited,as a result,thedegTaæ¤ion of starch was blocked.②malate dåŠydrogenase activity and lsoWmes 162eXpression侧s nhibä»–d,hs,he tncå’–å®lic acid cycle was obå’–cted.③cytochrme oxldase activity and lsocymes expression was inhibited,hence,thereå©lratory ele以ä¸on tfanå©ort slowedï¼doursl. å«å± c5缸咯e o(mabnå±±al4å’–y6yco血出uOæˆaå¨ by5e8Vy msmss må±±cme4oåŠCuZ",Cd'",Hg'"caused membrane 11pid Peroxidaion,among Which the ability ofCf"ca阳mg pçš¿xæ²¾æˆbnåˆ s the rdest.As a result of membranbranelipidperoxldalon,some p ortan physiological ictlons were altered:ï¼ he activaionenetgy of membraneï¼bound empmes increased, teopratUr of membrane phasechanges rose,nd rnelnbrane luldity decl*edï¼›ï¼ the NaZ"ï¼k'"ï¼ATPase activity nchondria decreased,especially under the condition of low teopratUre thedecreasing wasæ¤re slglllficant;③he freezing resistance ofwh...
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