维管植物的运输

Copyright©2005PearsonEducation,Inc.publishingasBenjaminCummingsPowerPointLecturesforBiology,SeventhEditionNeilCampbellandJaneReeceLecturesbyChrisRomeroChapter36TransportinVascularPlants維管植物的運輸Copyright©2005PearsonEducation,Inc.publishingasBenjaminCummings•Overview:PathwaysforSurvivalofvascularplant(維管植物存活途徑)•Forvascularplants,theevolutionaryjourney(演化之旅)ontolandinvolvedthedifferentiationoftheplantbodyintorootsandshoots(植物體分化為根與枝條)•Vasculartissuetransportsnutrientsthroughoutaplant;suchtransportmayoccuroverlongdistances(長途運輸)Figure36.1Copyright©2005PearsonEducation,Inc.publishingasBenjaminCummingsKeyConcepts•Concept36.1:Physicalforcesdrivethetransportofmaterialsinplantsoverarangeofdistances•Concept36.2:Rootsabsorbwaterandmineralsfromthesoil•Concept36.3:Waterandmineralsascendfromrootstoshootsthroughxylem(木質部)•Concept36.4:Stomatahelpregulatetherateoftranspiration(蒸散作用)•Concept36.5:Organicnutrientsaretranslocatedthroughthephloem(韌皮部)Copyright©2005PearsonEducation,Inc.publishingasBenjaminCummings•Concept36.1:Physicalforcesdrivethetransportofmaterialsinplantsoverarangeofdistances•Transportinvascularplantsoccursonthreescales(三種尺度/三種層次)–Transportofwaterandsolutesbyindividualcells,suchasroothairs(個別細胞水與溶質的運輸)–Short-distancetransportofsubstancesfromcelltocellatthelevelsoftissuesandorgans(組織與器官內細胞間物質的短距離運輸)–Long-distancetransportwithinxylemandphloematthelevelofthewholeplant(整株植物木質部與韌皮部的長距離運輸)Copyright©2005PearsonEducation,Inc.publishingasBenjaminCummings•Avarietyofphysicalprocesses(物理過程)areinvolvedinthedifferenttypesoftransport(眾多物理過程介入或參與不同型式的運輸)Figure36.2MineralsH2OCO2O2CO2O2H2OSugarLightSugarsareproducedbyphotosynthesisintheleaves.5Sugarsaretransportedasphloemsaptorootsandotherpartsoftheplant.6Throughstomata,leavestakeinCO2andexpelO2.TheCO2providescarbonforphotosynthesis.SomeO2producedbyphotosynthesisisusedincellularrespiration.4Transpiration,thelossofwaterfromleaves(mostlythroughstomata),createsaforcewithinleavesthatpullsxylemsapupward.3Waterandmineralsaretransportedupwardfromrootstoshootsasxylemsap.2Rootsabsorbwateranddissolvedmineralsfromthesoil.1Rootsexchangegaseswiththeairspacesofsoil,takinginO2anddischargingCO2.Incellularrespiration,O2supportsthebreakdownofsugars.7(木質液)(木質液)(蒸散作用)(韌皮液)Copyright©2005PearsonEducation,Inc.publishingasBenjaminCummingsSelectivePermeabilityofMembranes:AReview膜的選擇通透性----各種膜系統•Theselectivepermeability(選擇通透性)ofaplantcell’splasmamembrane(細胞膜)–Controlsthemovementofsolutesintoandoutofthecell•Specifictransportproteins/transportor(專一性輸送蛋白)–Enableplantcellstomaintainaninternalenvironmentdifferentfromtheirsurroundings•Solutesincell:cation(陽離子),anion(陰離子),neutralsolute(中性溶質)Copyright©2005PearsonEducation,Inc.publishingasBenjaminCummingsTheCentralRoleofProtonPumps(質子唧筒)•Protonpumps(質子唧筒)inplantcells–Createahydrogeniongradient(氫離子梯度)thatisaformofpotentialenergy(潛能)thatcanbeharnessed(=used)todowork(作功)–Contributetoavoltageknownasamembranepotential(膜電位),alsoakindofpotentialenergyFigure36.3CYTOPLASMEXTRACELLULARFLUIDATPH+H+H+H+H+H+H+H+ProtonpumpgeneratesmembranepotentialandH+gradient.–––––+++++Protonpump細胞質細胞外液Copyright©2005PearsonEducation,Inc.publishingasBenjaminCummings•Plantcellsuseenergystoredintheprotongradient(氫離子梯度)andmembranepotential(膜電位),bothofwhicharepotentialenergy–TodrivethetransportofmanydifferentsolutesFigure36.4a+CYTOPLASMEXTRACELLULARFLUIDCations(,forexample)aredrivenintothecellbythemembranepotential.Transportprotein(transportor)K+K+K+K+K+K+K+K+–––++(a)Membranepotentialandcationuptake(陽離子的吸收)––++transporter細胞質細胞外液Copyright©2005PearsonEducation,Inc.publishingasBenjaminCummings•Inthemechanismcalledcotransport(共同運輸)–Atransportprotein(cotransporter)couplesthepassageofonesolutetothepassageofanotherFigure36.4bH+H+H+H+H+H+H+H+H+H+H+H+–––+++–––+++NO3–(b)Cotransportofanions(陰離子的共同運輸)H+ofthroughacotransporter.Cellaccumulatesanions(,forexample)bycouplingtheirtransporttotheinwarddiffusion共同運輸蛋白高濃度H+低濃度NO3-低濃度H+高濃度NO3-cotransporter細胞質細胞外液Copyright©2005PearsonEducation,Inc.publishingasBenjaminCummingsFigure36.4c•The“coattail”effectofcotransport(共同運輸)–Isalsoresponsiblefortheuptakeofthesugarsucrose(neutralsolute)byplantcellsH+H+H+H+H+H+H+H+H+H+SPlantcellscanalsoaccumulateaneutralsolute,suchassucrose(),bycotransportingdownthesteepprotongradient.SH+–––+++––++–H+H+S+–(c)Cotransportofaneutralsolute(中性溶質的共同運輸)cotransporter細胞外液細胞質低濃度H+高濃度sugar高濃度H+低濃度sugarCopyright©2005PearsonEducation,Inc.publishingasBenjaminCummings報告完畢敬請指教！？！？！？！？！？！？Copyright©2005PearsonEducation,Inc.publishingasBenjaminCummingsEffectsofDifferencesinWaterPotential水勢差的效應•Tosurviveplantsmustbalancewateruptakeandloss•Differencesinwaterpotentialdrivewatertransportinplantcells(水勢差驅動植物細胞中的水份運輸)•Osmosis(滲透作用)–Determinesthenetuptakeorwaterlossbyacell–IsaffectedbysoluteconcentrationandpressureCopyright©2005PearsonEducation,Inc.publishingasBenjaminCummings•Osmoticpressure(滲透壓)inanimalcellslowosmoticpressure=low[solute]=high[water]highosmoticpressure=high[solute]=low[water]•Directionofmovingwaterlowosmoticpressure=low[solute]=high[water]higho