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Stresul hidric la plante

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Stresul hidric la plante. Prezentare realizata in cadrul proiectului POS CCE - A2-O 2 .1.2-2009-2 ID.524, cod SMIS-CSMR 11986 - PowerPoint PPT Presentation
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STRESUL HIDRIC LA PLANTE Prezentare realizata in cadrul proiectului POS 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
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Page 1: 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

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

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Raspunsul plantelor la factorul de stress de stress

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Activarea unor procese fiziologice

Alterarea metabolismului

celular

Ozone

Temperaturi extreme

inundatii

seceta

saruri

Recunoasterea stresului

Transducerea semnalului

(Lawlor, 2002)

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Ce reprezinta stresul hidric

Potentialul hidric al tesuturilor:

Mic: Ψcell ~-0.5 MPaModerate: Ψcell ~-0.5 to -1.5 MPaSever: Ψcell ~<-1.5 MPa

Continutul relativ de apa:

Mic: ~90%Moderat: 80-60%Sever: <50%

Creosote Bush: Larrea tridentata

Supraviatuire Ψcell of -11.5 MPa

Activitate fotosintetica – 5.0 to -8.0 MPa

)(

)(

DWSW

DWFW= R

Seceta include urmatoarele conditii:Deficit hidric al soplului , este cauzat de lipsa precipitatiilor si lipsa apei disponibile in sol.Deficit hidric al aerului , RH<20% in atmosfera, transpiratia>>absorbtia apei

Pressure Chamber TechniqueThermocouple Psychrometer Method

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Adaptare vs. Aclimatizare

Stress abiotic

aclimatizarea

Rezistenta- evitare- toleranta

Saguaro

Mojave desert star

Mojave desert star Impatiens capensis

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Modificari ale frunzelor

Dissected leaves in Palo Verde

SLA (specific leaf area)

Suprafata foliara/ substanta uscata

Desertice (xeric): 0.02 - 0.12Paduri uscate: 0.36 - 0.70Mezofite: 1.4 -1.6

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Scaderea suprafetei foliare

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)

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Sistemul radicular –crestrea ratei racina/lastari

Raporta sistem radicular/parte aeriana:

Paduri temparate: ~0.25savana ~0.3 – 0.4desert~0.6-0.9

Micoriza creste volumul radicular

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Deficitul hidric intensifica cresterea radacinilor

Tipul salbatic si mutante ABA-deficient de porumb cultivate in conditii normale si deficitare de apa

of

gro

wth

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Deficitul hidric provoaca abscizia frunzelor

Leaves of young cotton plants abscise in response to water stress

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… inchiderea stomatelor mediata de ABA

ROS – reactive oxygen species

PLC – phospholipase C

cADPR – cyclic ADP-ribose

IP3 – inositol triphosphate

PLC – phospho-lipase D

NO – Nitric oxide

PA – Phosphopatidic acid

R – Receptor

S1P – Spingosine-1- Phosphate

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Deficitul hidric scade rata fotosintezeiEfectul deficitului hidric asupra cresterii

frunzelor si a ratei fotsintezei la floarea soarelui

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Water stress affects translocation of nutrientsRelative 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.

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

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How does drought cause the generation of ROS?

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How does drought cause the generation of ROS?

3P680*

3O2 1O2*

O2 •O2– H2O2

SOD

SOD – Superoxide Dismutase

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Fates of sunlight absorbed in the light-harvesting chlorophyll complexes

Chl – chlorophyll 1Chl* – excited singlet chlorophyll3Chl* – excited triplet chlorophyll

P – photochemistry (green)D – safe dissipation of excess excitation energy as heat (red)F – fluorescence3T – triplet pathway, leading to the formation of singlet oxygen (1O2*) and photo-oxidative damage

Demmig-Adams & Adams III 2000 Nature 403: 371

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Actiunea ROS asupra celulelor

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3. Scavenging ROS

Enzymes:1) SOD( superoxide dismutase)2) POD (AscorbatPeroxidase)3) CAT (Catalase)

Oxidants:1) carotene2) Vit E3) Vit C 4) GSH5) phenolics

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