植物环境生理.ppt.convertor

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1、据估计,生物和非生物胁迫导致主要农作物产量下降65～85％作物最高产量（Kgha-1)平均产量损失（％）玉米19300460065.8小麦14500188082.1大豆7390161069.3植物对非生物胁迫的响应抗环境胁迫涉及到植物体的忍耐胁迫和逃避胁迫忍耐干旱的植物种类-肉质汁光合茎的仙人掌；避旱种类植物-深根系甜豆科植物和湿季沙漠之星。植物体改变适应机制的包括植物的渗透调节诸如菠菜和忍耐冻害的寒带植物黑云杉。Plantsrespondtostressbothascollectionsofcellsandaswholeorganisms.Stressesconstituteenviron

2、mentalsignalsthatarereceivedandrecognizedbytheplant.Afterstressrecognition,thesignaliscommunicatedwithincellsandthroughouttheplant.Transductionofenvironmentalsignalstypicallyresultsinalteredgeneexpressionatthecellularlevel,whichinturncaninfluencemetabolismanddevelopmentofwholeplant.Osmoticadjustmen

3、toccurswhentheconcentrationofsoluteswithinthecell.Thecellactivelyaccumulatessolutesand,asaresult,ψsdrop,promotingtheflowofwaterintothecell.Incellsthatfailtoadjustosmotically,solutesareconcentratedpassivelybutturgorislost.植物对水分胁迫的响应PlantgrowthisoftenlimitedbydroughtstressImagesource:IWMIDroughtstres

4、siscompoundedbyincreasedglobaltemperaturesInwarmregions,cropyieldscandrop~3–5%withevery1°Cincreaseintemperature.©EuropeanCommunities,1995-2009.ImageSource:ThePESETAProjectTemperaturechangeforecast2071-2100period,relativetothe1961-1990period.7EvenmilddroughtstressreducesyieldsMilddroughtstressreduce

5、stherateofphotosynthesisandgrowth,whereasextremedroughtstressislethal.WeneedplantsthatgrowwellevenunderstressfulconditionsHeatanddroughtstuntplantsandreducetheiryieldsWeneedplantsthatgrowwellevenunderstressfulconditionsHeatanddroughtstuntplantsandreducetheiryieldsMorelandmustbeclearedtogrowmorecrop

6、sWeneedplantsthatgrowwellevenunderstressfulconditionsHeatanddroughtstuntplantsandreducetheiryieldsMorelandmustbeclearedtogrowmorecropsRemovingtreestomakewayforcropsputsmoreCO2intotheatmosphereAlteringasinglegenecanincreaseplants’droughttoleranceYu,H.,etal.PlantCell2008;20:1134-1151Drought-resistant

7、Wild-typeAlargerrootsystemcontributestodroughttoleranceBreedingplantsforlargerrootsystemscanhelpthemgrowindrought-proneregions.Yu,H.,etal.PlantCell2008;20:1134-1151渗透胁迫是指植物与环境之间渗透势的不平衡导致的对植物的胁迫。干旱、盐胁迫等多种逆境都