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Stresul hidric la plante

Stresul hidric la plante. Prezentare realizata in cadrul proiectului POS CCE - A2-O 2 .1.2-2009-2 ID.524, cod SMIS-CSMR 11986

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Stresul hidric la plante

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  1. Stresulhidric la plante Prezentarerealizata in cadrulproiectuluiPOS CCE - A2-O 2.1.2-2009-2 ID.524, cod SMIS-CSMR 11986 CERCETARI PRIVIND SEMNIFICATIA RELATIEI DINTRE RASPUNSUL GENOMIC, METABOLISMUL FENOLPROPANILOR SI FOTOSINTEZA IN CONDITII DE STRES ABIOTIC PENTRU OPTIMIZAREA POTENTIALULUI BIOSINTETIC LA SOIURI DE ZMEUR SI MUR

  2. (Lawlor, 2002) Raspunsulplantelor la factorul de stress de stress Ozone Recunoasterea stresului Temperaturi extreme Transducerea semnalului inundatii seceta Activareaunorprocesefiziologice saruri Alterareametabolismuluicelular

  3. Cereprezintastresulhidric Seceta include urmatoareleconditii: Deficit hidric al soplului,estecauzat de lipsaprecipitatiilorsilipsaapeidisponibile in sol. Deficit hidric al aerului, RH<20% in atmosfera，transpiratia>>absorbtiaapei Potentialulhidric al tesuturilor: Mic: Ψcell ~-0.5 MPa Moderate: Ψcell ~-0.5 to -1.5 MPa Sever: Ψcell ~<-1.5 MPa Pressure Chamber Technique Thermocouple Psychrometer Method Continutulrelativ de apa: Mic: ~90% Moderat: 80-60% Sever: <50% SupraviatuireΨcell of -11.5 MPa Activitatefotosintetica– 5.0 to -8.0 MPa Creosote Bush: Larreatridentata

  4. Adaptare vs. Aclimatizare Saguaro Stress abiotic aclimatizarea Mojave desert star • Rezistenta • evitare • toleranta Impatiens capensis Mojave desert star

  5. Modificari ale frunzelor SLA (specific leaf area) Suprafatafoliara/ substantauscata Desertice(xeric): 0.02 - 0.12 Paduriuscate: 0.36 - 0.70 Mezofite: 1.4 -1.6 Dissected leaves in Palo Verde

  6. Scadereasuprafeteifoliare GR - growth rate ΨP – turgor Y - yield threshold (the pressure below which the cell wall resists nonreversible deformation) m - wall extensibility (the responsiveness of the wall to pressure)

  7. Sistemulradicular –crestrearateiracina/lastari Raportasistemradicular/parte aeriana: Paduritemparate: ~0.25 savana~0.3 – 0.4 desert~0.6-0.9 Micorizacrestevolumulradicular

  8. Deficitulhidricintensificacresterearadacinilor of growth Tipulsalbaticsimutante ABA-deficient de porumb cultivate in conditiinormalesideficitare de apa

  9. Deficitulhidricprovoacaabsciziafrunzelor Leaves of young cotton plants abscise in response to water stress

  10. … inchidereastomatelormediata de ABA cADPR – cyclic ADP-ribose ROS – reactive oxygen species IP3 – inositol triphosphate NO – Nitric oxide R – Receptor PA – Phosphopatidic acid PLC – phospho- lipase D S1P – Spingosine-1- Phosphate PLC – phospholipase C

  11. Deficitulhidricscade rata fotosintezei Efectuldeficituluihidricasupracresteriifrunzelorsi a rateifotsintezei la floareasoarelui

  12. Water stress affects translocation of nutrients Relative effects of water stress on photosynthesis and translocation in sorghum Plants exposed to 14CO2 for a short time interval. Radioactivity fixed in the leaf taken as a measure of photosynthesis, and loss of radioactivity after removal of 14CO2 taken as a measure of rate of assimilate translocation.

  13. A =gs ( Ca-Ci) A =gm (Ci-Cc)

  14. How does drought cause the generation of ROS?

  15. SOD O2•O2– H2O2 3P680* 3O21O2* How does drought cause the generation of ROS? SOD – Superoxide Dismutase

  16. Fates of sunlight absorbed in the light-harvesting chlorophyll complexes P – photochemistry (green) D – safe dissipation of excess excitation energy as heat (red) F – fluorescence 3T – triplet pathway, leading to the formation of singlet oxygen (1O2*) and photo-oxidative damage Chl – chlorophyll 1Chl* – excited singlet chlorophyll 3Chl* – excited triplet chlorophyll Demmig-Adams & Adams III 2000 Nature 403: 371

  17. Actiunea ROS asupracelulelor

  18. 3. Scavenging ROS • Enzymes： • SOD（superoxide dismutase) • POD (AscorbatPeroxidase) • CAT (Catalase) • Oxidants： • carotene • Vit E • Vit C • GSH • phenolics

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