Aula HORMÔNIOS VEGETAIS META Estudar os efeitos dos hormônios vegetais nas plantas. OBJETIVOS $R¿QDOGHVWDDXODRDOXQRGHYHUi HQWHQGHUDVIXQo}HVHHIHLWRVGRVKRUP{QLRVYHJHWDLVQDVSODQWDV 35e5(48,6,72 &RQKHFHUQRo}HVEiVLFDVGHFUHVFLPHQWRYHJHWDO )RQWHKWWSZZZÁRUHVRQOLQHFRP 9 Fisiologia Vegetal INTRODUÇÃO +RUP{QLRV YHJHWDLV VmR FRPSRVWRV RUJkQLFRV QmR QXWULHQWHV SURGX]LGRVSRUSODQWDVJHUDOPHQWHHPXPORFDOGLIHUHQWHGDTXHOHRQGHVmR XVDGRV7DLVKRUP{QLRVHPEDL[DVFRQFHQWUDo}HVUHJXODPRFUHVFLPHQWR HDVUHDo}HVÀVLROyJLFDVGDVSODQWDV5HFHQWHPHQWHXPDJUDQGHTXDQWLGDGH GHKRUP{QLRVYHJHWDLVIRLVLQWHWL]DGDHDOJXQVVmRXVDGRVFRPHUFLDOPHQWH para matar ervas daninhas ou cultivar frutas. $VSODQWDVVmRDOWDPHQWHRUJDQL]DGDVWDQWRHPWHUPRVGHIRUPDTXDQWR GHIXQomR6mRRVKRUP{QLRVYHJHWDLVTXHFRRUGHQDPHLQWHJUDPRVSURFHVVRVGHFUHVFLPHQWRGDVSODQWDVHTXHSURYRFDPHVVHQtYHOGHRUJDQL]DomR 2 DVSHFWR GR FRQWUROH GR FUHVFLPHQWR GDV SODQWDV ÀFD SDUWLFXODUPHQWH HYLGHQWHQRHVWXGRGHWHFLGRVYHJHWDLV3RUH[HPSORVHDVFpOXODVYLYDVTXH QmRSHUGHUDPDFDSDFLGDGHGHVHGLYLGLUIRUHPUHPRYLGDVGHXPDSODQWDUHWRPDUmRRFUHVFLPHQWRDWLYRVHUHFHEHUHPQXWULHQWHVHVVHQFLDLVHKRUP{QLRV GHFUHVFLPHQWR(QWUHWDQWRVHRHTXLOtEULRHQWUHRVGLIHUHQWHVKRUP{QLRV QmRIRUH[WUHPDPHQWHSUHFLVRRUHVXOWDGRVHUiRFUHVFLPHQWRGHPDVVDV WXPRUDLVGHFpOXODVYHJHWDLVTXHSDUHFHUmRWHUSHUGLGRFRPSOHWDPHQWHR FRQWUROHGRVHXSRGHUGHRUJDQL]DomRHGHHVWUXWXUDomR3RURXWURODGR DRDOWHUDURHTXLOtEULRHDFRQFHQWUDomRGHKRUP{QLRVGHSODQWDVQRPHLR de cultura, os cientistas podem desenvolver plantas completas, com raiz HFRSDHWRGDVDVVXDVFDUDFWHUtVWLFDVWtSLFDVDSDUWLUGHXPD~QLFDFpOXOD 0XLWDVGDVFKDPDGDV´SODQWDVGHSURYHWDµVmRSURGX]LGDVGHVVDIRUPD $DomRKRUPRQDOHVWiGLUHWDPHQWHUHODFLRQDGDDRGHVHQYROYLmento dos vegetais (Fonte: http://www.brasilescola.com). 88 Hormônios vegetais Aula PRINCIPAIS CLASSES DE HORMÔNIOS VEGETAIS 9 2V KRUP{QLRV YHJHWDLV SRGHP VHU DJUXSDGRV HP GLYHUVDV FODVVHV SULQFLSDLV (VVDV FODVVHV VmR GHWHUPLQDGDV SHODV FDUDFWHUtVWLFDV TXtPLFDV GRVKRUP{QLRVRXSHORVHIHLWRVTXHH[HUFHPVREUHDVSODQWDV2VJUXSRV RXFODVVHVGHKRUP{QLRVYHJHWDLVRXÀWRUP{QLRVVmRGLYLGLGRVHPFLQFR $X[LQDV&LWRFLQLQDV*LEHUHOLQDV$FLGRDEVFtVLFR(WLOHQR FITOHORMÔNIOS OU REGULADORES DO CRESCIMENTO )LJXUD([SHULrQFLDVTXHOHYDUDP à descoberta dos hormônios vegetais (Fonte: www.herbario.com.br). AUXINAS 6mRRVFRPSRVWRVTXHSURYRFDPRDORQJDPHQWRQDVFpOXODVGRVEURWRV GHSODQWDV$VDX[LQDVVmRVLQWHWL]DGDVHDSUHVHQWDPDVFRQFHQWUDo}HVPDLV altas nas áreas meristemáticas do broto e da raiz, áreas nas quais as células VHGLYLGHPUDSLGDPHQWHSDUDUHQRYDURVHXFUHVFLPHQWR$VDX[LQDVVmR deslocadas por toda a planta a partir dessas áreas. 89 Fisiologia Vegetal 4XDQGR DSOLFDGD H[WHUQDPHQWHjV H[WUHPLGDGHVGH FDXOHVLQFLVRV D DX[LQD HVWLPXOD VXD IRUPDomR (P GRVDJHQV H[FHVVLYDV SRUpP LQLEH D IRUPDomRGHUDt]HV(PJHUDORWHFLGRGDUDL]pFRQVLGHUDYHOPHQWHPDLV VHQVtYHOjDX[LQDGRTXHRWHFLGRGRFDXOH3RUWDQWRDVFRQFHQWUDo}HVGH DX[LQDPDLVIDYRUiYHLVSDUDRDORQJDPHQWRGRFDXOHQRUPDOPHQWHUHVXOWDP QDLQLELomRGRGHVHQYROYLPHQWRGDUDL] (VVDVHQVLELOLGDGHGLIHUHQFLDGDID]FRPTXHDVH[WUHPLGDGHVGREURWRGDV SODQWDVDSUHVHQWHPXPJHRWURSLVPRQHJDWLYRLVWRpÀTXHPYROWDGDVSDUDFLPD TXDQGRFRORFDGDVHPSRVLomRKRUL]RQWDOQHVVDVPHVPDVFRQGLo}HVDVH[WUHPLGDGHV GDUDL]DSUHVHQWDPXPJHRWURSLVPRSRVLWLYRRXVHMDÀFDPYROWDGDVSDUDEDL[R SDUDGHQWURGRVROR4XDQGRDJUDYLGDGHID]FRPTXHDDX[LQDVHDFXPXOHQDSDUWH LQIHULRUGRFDXOHDVFpOXODVPDLVEDL[DVVHDORQJDPPDLVGRTXHDVGHFLPDID]HQGR FRPTXHDH[WUHPLGDGHTXHHVWiHPFUHVFLPHQWRVHYROWHSDUDFLPD1RFDVRGDUDL] HQWUHWDQWRDVLWXDomRpLQYHUVD$FRQFHQWUDomRPDLRUGHDX[LQDQDSDUWHLQIHULRU inibe o alongamento das células naquele local, e o alongamento relativamente PDLRUGDVFpOXODVVXSHULRUHVID]FRPTXHDH[WUHPLGDGHGDUDL]VHYROWHSDUDEDL[R EFEITOS DA AUXINA $VDX[LQDVSRGHPSURGX]LUGLYHUVRVHIHLWRVLQWHUHVVDQWHVQRVYHJHWDLV tais como: VmR DWLYDV HP TXDQWLGDGHV PXLWR SHTXHQDV H TXDQGR DSOLFDGDV HP TXDQWLGDGHVPXLWRHOHYDGDVSRGHPPDWDURYHJHWDO FRPRVmRWUDQVSRUWDGDVGDFRSDSDUDDVEDVHDVDX[LQDVWHQGHPDVH FRQFHQWUDUQDVUDt]HVRQGHVHDFXPXODPHPOLJHLURH[FHVVRHUHWDUGDPR crescimento. No caule, ao contrário, sempre há menos hormônio do que RLGHDOSDUDRFUHVFLPHQWReSRULVVRTXHXPOLJHLURDFUpVFLPRGHDX[LQD UHWDUGDRFUHVFLPHQWRGDVUDt]HVHDFHOHUDRGRFDXOH DVDX[LQDVSURGX]LGDVSHORyYXORIHFXQGDGRSURYRFDPDWUDQVIRUPDomR GDVSDUHGHVGRRYiULRQRIUXWRÀJXUD )LJXUD7UDQVIRUPDomRGDVSDUHGHVGRRYiULRQRIUXWR SHODVDX[LQDVZZZFLDJULXVSEU 90 Hormônios vegetais Aula eSRULVVRTXHVHLPSHGLUPRVDIHFXQGDomRGRyYXORHDSOLFDUPRVXPD SHTXHQDTXDQWLGDGHGHDX[LQDQDVSDUHGHVGRRYiULRREWHUHPRVIUXWRV partenogenéticos, sem sementes. DVDX[LQDVFRPRMiYLPRVSURYRFDPDVFXUYDWXUDVGRVYHJHWDLVFDXVDGDV SHODJUDYLGDGHJHRWURSLVPRHSHODOX]IRWRWURSLVPR RVEURWRVTXHÀFDPQDH[WUHPLGDGHVXSHULRUGRVFDXOHVHGRVUDPRV SURGX]HPDX[LQDVTXHDRGHVFHUHPDRORQJRGRFDXOHLQLEHPRGHVHQvolvimento da maioria das gemas laterais(dominância apical), impedindo TXHVHGHVHQYROYDPIRUPDQGRUDPRV 6HFRUWDUPRVREURWRWHUPLQDOGRFDXOHSDUDQGRGHGHVFHUDX[LQDRV brotos laterais se desenvolvem formando novos ramos. RVIUXWRVHDVIROKDVSRVVXHPDFDPDGDGHDEVFLVmRÀJXUDSHODTXDO FDHP(VWDFDPDGDQmRVHIRUPDHQTXDQWRRIUXWRHDIROKDVmRYHUGHVHSURGX]HPDX[LQDV$RDPDGXUHFHUHPRVIUXWRVHDVIROKDV DDX[LQDGHL[DGHVHUSURGX]LGDHDFDPDGDGHabscisão se forma e provoca a sua queda. HPGRVHVUHODWLYDPHQWHSHTXHQDVDVDX[LQDVSURYRFDP o enraizamento de estacas, sendo, por isso, muito úteis na UHSURGXomRDVVH[XDGDGRVYHJHWDLV DVVRFLDGDV D RXWURV SURGXWRV DV DX[LQDV VmR usadas na cultura de células e tecidos vegetais, fa]HQGR FRP TXH KDMD QmR DSHQDV GLYLVmR FHOXODU FRPRGLIHUHQFLDomR(VWHSURFHVVRGHQRPLQDGRGH ´PLFURSURSDJDomRµSHUPLWHTXHVHIDoDDSDUWLUGH DOJXPDVFpOXODVDFORQDJHPGHLQGLYtGXRV AUXINAS E REGULADORES DE CRESCIMENTO 9 $EVFLVmR Refere-se à perda de uma parte do corpo. É normalmente referido para descrever o processo através do qual uma planta perde uma ou mais partes da sua estrutura: folha, semente, fruto. )LJXUD &DPDGD GH $EVFLVmR (Fonte: www.homestead.com). 2iFLGRLQGRODFpWLFRpDDX[LQDQDWXUDOTXHSURGX]LGDSHORYHJHWDO FRQWURODPXLWRVGHVHXVSURFHVVRVPHWDEyOLFRV ([LVWHP RXWURV SURGXWRV FRPR RV iFLGRV QDIWDOHQRDFpWLFR LQGRO EXWtULFRHLQGROSURSL{QLFRTXHWrPHIHLWRVVHPHOKDQWHVHTXHFRPRQmR VmRQDWXUDOPHQWHSURGX]LGRVSHORVYHJHWDLVQmRGHYHPVHUFKDPDGRVGH hormônios, mas de reguladores de crescimento. GIBERELINA $KLVWyULDLQLFLDOGDVJLEHUHOLQDVIRLXPSURGXWRH[FOXVLYRGRVFLHQWLVWDV MDSRQHVHV(P(.XURVDZDHVWXGDYDXPDGRHQoDGHDUUR]2U\]DVDWLYDGHQRPLQDGDGHGRHQoDGDV´SODQWLQKDVORXFDVµQDTXDODSODQWDFUHVFLD 91 Fisiologia Vegetal UDSLGDPHQWHHUDDOWDFRPFRORUDomRSiOLGDHDGRHQWDGDFRPWHQGrQFLDDFDLU .XURVDZDGHVFREULXTXHDFDXVDGHWDOGRHQoDHUDXPDVXEVWkQFLDSURGX]LGD SRUXPDHVSpFLHGHIXQJR*LEEHUHOODIXMLNXURLRTXDOSDUDVLWDYDDVSOkQWXODV $JLEHUHOLQDIRLDVVLPGHQRPLQDGDHLVRODGDHP$VJLEHUHOLQDVHVWmR presentes possivelmente em todas as plantas, por todas as suas partes e em GLIHUHQWHVFRQFHQWUDo}HVVHQGRTXHDVPDLVDOWDVFRQFHQWUDo}HVHVWmRHP VHPHQWHVDLQGDLPDWXUDV0DLVGHJLEHUHOLQDVMiIRUDPLVRODGDVHLGHQWLÀFDGDVTXLPLFDPHQWH2JUXSRPDLVEHPHVWXGDGRpR*$FRQKHFLGRSRU DFLGRJLEHUpOLFRTXHpWDPEpPSURGX]LGRSHORIXQJR*LEEHUHOODIXMLNXURL As giberelinas têm efeitos drásticos no alongamento dos caules e folhas GHSODQWDVLQWDFWDVDWUDYpVGDHVWLPXODomRWDQWRGDGLYLVmRFHOXODUFRPR do alongamento celular. LOCAIS DE PRODUÇÃO DAS GIBERELINAS NO VEGETAL $VJLEHUHOLQDVVmRSURGX]LGDVHPWHFLGRVMRYHQVGRVLVWHPDFDXOLQDUHVHPHQWHVHPGHVHQYROYLPHQWReLQFHUWRVHVXDVtQWHVHRFRUUHWDPEpPQDVUDt]HV$SyV DVtQWHVHDVJLEHUHOLQDVVmRSURYDYHOPHQWHWUDQVSRUWDGDVSHOR[LOHPDHÁRHPD GIBERELINAS E OS MUTANTES ANÕES $SOLFDQGRJLEHUHOLQDHPSODQWDVDQmVYHULÀFDVHTXHHODVVHWRUQDP LQGLVWLQJXtYHLVGDVSODQWDVGHDOWXUDQRUPDOSODQWDVQmRPXWDQWHVLQGLFDQGRTXHDVSODQWDVDQmVPXWDQWHVVmRLQFDSD]HVGHVLQWHWL]DUJLEHUHOLQDV e que o crescimento dos tecidos requer este regulador. GIBERELINAS E AS SEMENTES Em muitas espécies de plantas, incluindo o alface, o tabaco e a aveia selvagem, as giberelinas quebram a dormência das sementes, promovendo RFUHVFLPHQWRGRHPEULmRHDHPHUJrQFLDGDSOkQWXOD(VSHFLÀFDPHQWHDV JLEHUHOLQDVHVWLPXODPRDORQJDPHQWRFHOXODUID]HQGRFRPTXHDUDGtFXOD rompa o tegumento da semente. GIBERELINAS E DESENVOLVIMENTO DE FRUTOS *LEHUHOLQDVDVVLPFRPRDX[LQDVSRGHPFDXVDURGHVHQYROYLPHQWRGH IUXWRVSDUWHQRFiUSLFRVVHPVHPHQWHVLQFOXLQGRPDomDEyERUDEHULQMHOD HJURVHOKD$PDLRUDSOLFDomRFRPHUFLDOGDVJLEHUHOLQDVpQDSURGXomRGH XYDVSDUDDPHVD2iFLGRJLEHUpOLFRSURPRYHDSURGXomRGHIUXWRVJUDQGHV sem sementes, soltos entre si. 92 Hormônios vegetais APLICAÇÕES PRÁTICAS DAS GIBERELINAS *LEHUHOLQDVSRGHPVHUXVDGDVQDTXHEUDGHGRUPrQFLDGHVHPHQWHVGH YiULDVHVSpFLHVGHYHJHWDLVDFHOHUDQGRDJHUPLQDomRXQLIRUPHGHSODQWDo}HV(P VHPHQWHVGHFHYDGDHRXWUDVJUDPtQHDVDJLEHUHOLQDSURGX]LGDSHORHPEULmR DFHOHUDDGLJHVWmRHPUHVHUYDVQXWULWLYDVFRQWLGDVQRHQGRVSHUPDUHJLmRULFD HPUHVHUYDVSRLVHVWLPXODDSURGXomRGHHQ]LPDVKLGUROtWLFDV *LEHUHOLQDV SRGHP VHU XVDGDV SDUD DQWHFLSDU D SURGXomR GH VHmentes em plantas bienais. Juntamente com as citocininas, desempenham LPSRUWDQWHSDSHOQRSURFHVVRGHJHUPLQDomRGHVHPHQWHV *LEHUHOLQDVHDX[LQDVVmRODUJDPHQWHXWLOL]DGDVSDUDDSURGXomRGH IUXWRVSDUWHQRFiUSLFRVVHPVHPHQWHV*LEHUHOLQDVHVWLPXODPRÁRUHVFLPHQWRGHSODQWDVGHGLDORQJR3'/HELHQDLV CITOQUININAS Aula 9 6HQHVFrQFLD É o processo de envelhecimento dos seres vivos - quando as células deixam de se dividir para substituírem outras células que, por alguma razão, deixaram de metabolizar. &LWRTXLQLQDVRXTXLQLQDVpJUXSRGHKRUP{QLRVTXHSURPRYHDGLYLVmRFHOXODUDRLQYpVGRDORQJDPHQWRFHOXODU$VFLWRTXLQLQDVVXUJHPQDV UDt]HVGDVSODQWDVHVmRWUDQVSRUWDGDVSDUDFLPDDWpRVEURWRVeSRVVtYHO que também se originem em algumas folhas e brotos jovens. A primeira citoquinina a ser conhecida, a cinetina, foi isolada de um animal (do ADN do sêmen do arenque). Mas outras têm ampla ocorrência em plantas e já foram isoladas e caracterizadas quimicamente. $VFLWRTXLQLQDVSDUHFHPVHUDVJUDQGHV´QRUPDWL]DGRUDVµGRFUHVFLPHQWR de plantas. Têm um papel importante no desenvolvimento controlado e organizado da forma e da estrutura das plantas superiores. Quando adicionadas a culturas assépticas nas concentrações adequadas, as citoquininas provocam a GLIHUHQFLDomRGRVJUXSRVGHFpOXODVTXHIRUPDPRVWHFLGRVTXHHYHQWXDOPHQWH VHWRUQDUmRDVGLIHUHQWHVSDUWHVGDVSODQWDV$GHVFREHUWDGHVVHIDWRQDGpFDGD GHHVWDEHOHFHXRDUFDERXoRSDUDVXFHVVRVH[SHULPHQWDLVSRVWHULRUHV1R LQtFLRGDGpFDGDGHMiVHFULDYDPSODQWDVLQWHLUDVVXVSHQVDVHPPHLRV QXWULWLYRVDUWLÀFLDLVDSDUWLUGHFpOXODV~QLFDVHLQGLIHUHQFLDGDV 2XWUDIXQomRLPSRUWDQWHGDFLWRTXLQLQDpDLQLELomRGDsenescência, isto é, GRHQYHOKHFLPHQWRSULQFLSDOPHQWHHPFXOWXUDVGHYHJHWDLVGHIROKDVYHUGHV2V KRUP{QLRVDXPHQWDPDUHWHQomRGHDOJXPDVVXEVWkQFLDVWDLVFRPRDPLQRiFLGRVGHQWURGDFpOXOD&RQVHTXHQWHPHQWHWDLVVXEVWkQFLDVSRGHPUHWRUQDUDR FLFORDWUDYpVGDVtQWHVHGHSURWHtQDVTXHVmRHVVHQFLDLVSDUDRFUHVFLPHQWR HDUHSDUDomRGHWHFLGRV'HVVHPRGRRHQYHOKHFLPHQWRRDPDUHOHFLPHQWR HDFRQVHTXHQWHSHUGDGHTXDOLGDGHPHUFDGROyJLFDGRVSURGXWRVFROKLGRV é consideravelmente retardada. Uma citoquinina sintética, a benziladenina, HVWiFRPHoDQGRDVHUXVDGDH[SHULPHQWDOPHQWHFRPRLQLELGRUGHVHQHVFrQFLDHPPXLWRVWLSRVGHSODQWDVYHUGHVWDLVFRPRDOIDFHEUyFROLVHDLSR 93 Fisiologia Vegetal ETILENO 2HWLOHQRpRFRPSRVWRRUJkQLFRHQGyJHQRRXH[yJHQRPDLVVLPSOHV HDSDUHQWHPHQWHR~QLFRJiVTXHSDUWLFLSDGHUHJXODomRGRVSURFHVVRV ÀVLROyJLFRVGDVSODQWDV2HWLOHQRpFRQVLGHUDGRXPKRUP{QLRMiTXHp XPSURGXWRQDWXUDOGRPHWDEROLVPRDWXDHPFRQFHQWUDo}HVPXLWREDL[DV HSDUWLFLSDGDUHJXODomRGHSUDWLFDPHQWHWRGRVRVSURFHVVRVGHGHVHQYROvimento e crescimento das plantas. A vantagem original do gás etileno como regulador do crescimento reside QRIDWRGHTXHQmRH[LJHDWLYLGDGHPHWDEyOLFDSDUDVHXWUDQVSRUWHHHPFHUWRV FDVRVSDUDVXDLQDWLYDomR$GLIXVmRGRJiVpVXÀFLHQWHSDUDVHXWUDQVSRUWHH SDUDGLPLQXLUVXDFRQFHQWUDomR$PDLRUGLÀFXOGDGHGRVHVWXGRVFRPRJiV etileno é que ele está geralmente presente na atmosfera, particularmente nas áreas de atividade industrial ou de trânsito intenso. Além disso, praticamente todos RVFRPSRVWRVRUJkQLFRVOLEHUDPHWLOHQRTXDQGRVmRDTXHFLGRVRXR[LGDGRV Finalmente, as plantas sujeitas à vários tipos de estresse, como o ataque GHLQVHWRVHPLFURUJDQLVPRVRFRQWDWRFRPVXEVWkQFLDVWy[LFDVDFRORFDomR HPSRVLomRKRUL]RQWDODH[SRVLomRDEDL[DVWHPSHUDWXUDVHDSUHVHQoDGH SRWHQFLDLVGHiJXDEDL[RVQRVWHFLGRVSURGX]HPHWLOHQRDFLPDGRVQtYHLV esperados em plantas normais. ÁCIDO ABSCÍSICO 1RVSHUtRGRVIDYRUiYHLVjYHJHWDomRDVJHPDVGDSODQWDÀFDPHPLQWHQVD atividade, dividindo constantemente as suas células e promovendo o cresciPHQWRYHJHWDO1RVSHUtRGRVGHVIDYRUiYHLVDVJHPDVGHYHPSHUPDQHFHUHP UHSRXVRHSURWHJLGDVSDUDQmRPRUUHU)RLREVHUYDGRTXHDQWHVGRSHUtRGR GHVIDYRUiYHODSODQWDSURGX]KRUP{QLRiFLGRDEVFtVLFRTXHpUHVSRQViYHO pela dormência das gemas do caule e pela queda das folhas. 2VHIHLWRVVmRIHFKDPHQWRGRVHVW{PDWRVLQGXomRGRWUDQVSRUWHGHIRWRVVLQWHWL]DGRVGDVIROKDVSDUDDVVHPHQWHVHPGHVHQYROYLPHQWRLQGXomRGDVtQWHVH GHSURWHtQDVGHUHVHUYDHPVHPHQWHVHPEULRJrQHVHTXHSRGHDIHWDUDLQGXomRH PDQXWHQomRGDGRUPrQFLDHPVHPHQWHVHJHPDVGHFHUWDVHVSpFLHV CONCLUSÃO 3DUDÀQDOL]DUJRVWDUtDPRVTXHYRFrSHUFHEHVVHDLPSRUWkQFLDGRV hormônios vegetais como reguladores do crescimento das plantas suSHULRUHV8PKRUP{QLRpXPDVXEVWkQFLDTXtPLFDSURGX]LGDHPFHUWRV tecidos do organismo e transportada para outros tecidos onde provoca XPDUHVSRVWDÀVLROyJLFD 94 Hormônios vegetais 2KRUP{QLRpXPDVXEVWkQFLDDWLYDHPTXDQWLGDGHH[WUHPDPHQWH SHTXHQDSRULVVRpLPSRUWDQWHTXHYRFrVDLEDLGHQWLÀFDUDVVXDVIXQo}HV e efeitos nas plantas. 1D DJULFXOWXUD D DX[LQD H JOLEHUHOLQD VmR SXOYHUL]DGDV QDV FXOWXUDV (VVDVVXEVWkQFLDVSURYRFDPDÁRUDomRVLPXOWkQHDGHSODQWDo}HVGHDEDFD [LHYLWDPDTXHGDSUHPDWXUDGHODUDQMDVHSHUPLWHPDIRUPDomRGHXYDV sem sementes. Aumentam, ainda, o tempo de armazenamento de batatas, impedindo o brotamento de suas gemas. $ XWLOL]DomR GH KRUP{QLRV YHJHWDLV FRPR D ²' iFLGR GLFORUR IHQR[LDFpWLFRXPDDX[LQDVLQWpWLFDTXHpXPKHUELFLGDVHOHWLYRpLQyFXD SDUDJUDPtQHDVFRPRDUUR]WULJRFHQWHLRSRUpPPDWDHUYDVGDQLQKDVGH IROKDVODUJDVFRPRFDUUDSLFKRVSLF}HVGHQWHVGHOHmR Aula 9 RESUMO Nesta aula você pode observar o efeito dos hormônios vegetais como substâncias reguladoras do crescimento das plantas superiores. 2VKRUP{QLRVHPEDL[DVFRQFHQWUDo}HVUHJXODPRFUHVFLPHQ WR H DV UHDo}HV ÀVLROyJLFDV GDV SODQWDV 5HFHQWHPHQWH XPD JUDQGH TXDQWLGDGHGHKRUP{QLRVYHJHWDLVIRLVLQWHWL]DGDHDOJXQVVmRXVDGRV comercialmente para matar ervas daninhas ou cultivar frutas. Podem VHUDJUXSDGRVHPGLYHUVDVFODVVHVSULQFLSDLV(VVDVFODVVHVVmRGHWHU PLQDGDVSHODVFDUDFWHUtVWLFDVTXtPLFDVGRVKRUP{QLRVRXSHORVHIHLWRV TXH H[HUFHP VREUH DV SODQWDV 2V JUXSRV RX FODVVHV GH KRUP{QLRV YHJHWDLVRXÀWRUP{QLRVVmRGLYLGLGRVHPFLQFR$X[LQDV&LWRFLQLQDV *LEHUHOLQDV$FLGRDEVFtVLFR(WLOHQR $VDX[LQDVVmRRVFRPSRVWRVTXHSURYRFDPRDORQJDPHQWRQDVFpOXODV GRVEURWRVGHSODQWDV$VDX[LQDVVmRVLQWHWL]DGDVHDSUHVHQWDPDVFRQFHQWUD ções mais altas nas áreas meristemáticas do broto e da raiz, áreas nas quais as FpOXODVVHGLYLGHPUDSLGDPHQWHSDUDUHQRYDURVHXFUHVFLPHQWR$VDX[LQDV VmRGHVORFDGDVSRUWRGDDSODQWDDSDUWLUGHVVDViUHDV As giberelinas têm efeitos drásticos no alongamento dos caules e IROKDVGHSODQWDVLQWDFWDVDWUDYpVGDHVWLPXODomRWDQWRGDGLYLVmRFHOXODU FRPRGRDORQJDPHQWRFHOXODU&LWRTXLQLQDVRXTXLQLQDVVmRJUXSRVGH KRUP{QLRVTXHSURPRYHPDGLYLVmRFHOXODUDRLQYpVGRDORQJDPHQWR FHOXODU$VFLWRTXLQLQDVVXUJHPQDVUDt]HVGDVSODQWDVHVmRWUDQVSRUWDGDV para cima até os brotos. 2HWLOHQRpRFRPSRVWRRUJkQLFRHQGyJHQRRXH[yJHQRPDLVVLPSOHVH DSDUHQWHPHQWHR~QLFRJiVTXHSDUWLFLSDGHUHJXODomRGRVSURFHVVRVÀVLROyJLFRV das plantas, participando de praticamente todos os processos de crescimento, GHVHQYROYLPHQWRGDVSODQWDV2iFLGRDEVFtVLFRpUHVSRQViYHOSHODGRUPrQFLD das gemas do caule e pela queda das folhas. 95 Fisiologia Vegetal ATIVIDADES $VÀJXUDV,,,H,,,UHSUHVHQWDPXPH[SHULPHQWRUHDOL]DGRSRU&'DUZLQ HVHXÀOKR)UDQFLVVREUHRFUHVFLPHQWRGDVSODQWDVHSXEOLFDGRHP $QDOLVHDVHMXOJXHRVLWHQVDEDL[RÀJXUD )LJXUD ([SHULPHQWR GH 'DUZLQ )RRQWH ZZZ herbario.com.br). eSUHFLVRLOXPLQDUDH[WUHPLGDGHGDSODQWDSDUDTXHHODFUHVoDHPGL UHomRjOX] $OJXPDLQÁXrQFLDpWUDQVPLWLGDGDSDUWHVXSHULRUSDUDDSDUWHLQIHULRU da planta, provocando a sua curvatura. 3. A curvatura da planta ocorre porque o lado iluminado cresce mais do TXHRODGRQmRLOXPLQDGR $VH[SHULrQFLDVGH'DUZLQUHIHUHPVHDRIRWRWURSLVPRSRVLWLYRGRVFDXOHV $VSODQWDVQmRFUHVFHPHPDXVrQFLDGHOX] $SDUWLUGHVWHVH[SHULPHQWRV&KDUOHV'DUZLQGHVFREULXDDX[LQD COMENTÁRIO SOBRES A ATIVIDADES 4XHVWmR2JUDXVHJXQGRRTXDOXPDSODQWDVHFXUYDVREFRQGLo}HV H[SHULPHQWDLVIRUQHFHXPHQVDLRELROyJLFRFRPXPSDUDDDX[LQD8P HQVDLRELROyJLFRpXPPpWRGRSDUDGHWHUPLQDUTXDQWLWDWLYDPHQWHD FRQFHQWUDomRGHXPDVXEVWkQFLDSHORVHXHIHLWRVREUHRFUHVFLPHQWR de um organismo apropriado sob condições controladas. PRÓXIMA AULA 1DSUy[LPDDXODLUHPRVHVWXGDUUHSURGXomRGDVSODQWDV 96 Hormônios vegetais AUTOAVALIAÇÃO Aula 9 4XDODIXQomRGRiFLGRDEVFtVLFRQDSODQWD" 4XDOKRUP{QLRYHJHWDOpUHVSRQViYHOSHORDPDGXUHFLPHQWRGRVIUXWRV" 3. Quando se poda uma roseira, observa-se um rápido crescimento das JHPDVODWHUDLVSDUDDIRUPDomRGHUDPRVYHJHWDWLYRV,VWRRFRUUHSRUTXH as gemas laterais: DSDVVDPDSURGX]LUPHQRVDX[LQDV ELQWHQVLÀFDPDSURGXomRGHHWLOHQRHJLEHUHOLQDV FUHFHEHPPHQRVFLWRFLQLQDV GSDVVDPDUHFHEHUPDLVDX[LQDV HUHFHEHPPHQRVDX[LQDV TXDQGRVHHOLPLQDDJHPDDSLFDOGHXPDURVHLUDJHUDOPHQWHHVWD DFRQWLQXDDFUHVFHUQRUPDOPHQWHSDUDFLPD ESDUDFRPSOHWDPHQWHGHFUHVFHU FIRUPDJHPDVODWHUDLVTXHUHJULGHP GGHVHQYROYHDVJHPDVODWHUDLVHUDPLÀFDVH e) forma uma nova gema apical em lugar da eliminada. $V FDPDGDV GH DEVFLVmR FRQVWLWXHP HVWUDWRV GH FpOXODV FRP SDUHGHV FHOXODUHV GHOJDGDV H HP GHVLQWHJUDomR $ IRUPDomR GHVWDV FDPDGDV OHYD jVHSDUDomRSURJUHVVLYDGRVIUXWRVSHUPLWLQGRDVXDTXHGD$IRUPDomR destas camadas está relacionada, pelo menos em parte, com: DRGHVHQYROYLPHQWRGDVJHPDVODWHUDLV EDGLPLQXLomRQDWD[DGHDX[LQDVQRVIUXWRV FRDXPHQWRGDTXDQWLGDGHGHSURWHtQDV GRDXPHQWRQDDEVRUomRL{QLFDSHODVUDt]HV HDHOLPLQDomRGDVJHPDVDSLFDLVGRFDXOH REFERÊNCIAS )(55(,5$/*5Fisiologia vegetal: 5HODo}HV+tGULFDV Fortaleza: (GLo}HV8)& +23.,16:*Introduction to plant physiologyHG1HZ<RUN -RKQ:LOH\6RQV,QF 5$9(13+(9(575)(,&++2516(Biologia vegetal. 6 ed. 5LRGH-DQHLUR*XDQDEDUD.RRJDQ 7$,=/=(,*(5(Fisiologia vegetalHG(GLWRUD$UWPHG 97