Transcript 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
(Lawlor, 2002)
Ozone
Recunoasterea
stresului
Temperaturi
extreme
Transducerea
semnalului
inundatii
seceta
Activarea unor procese
fiziologice
saruri
Alterarea
metabolismului
celular
2
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
Potentialul hidric al
tesuturilor:
Pressure Chamber Technique
Thermocouple Psychrometer Method
Mic: Ψcell ~-0.5 MPa
Moderate: Ψcell ~-0.5 to -1.5 MPa
Sever: Ψcell ~<-1.5 MPa
R=
Continutul relativ de apa:
( FW  DW )
( SW  DW )
Mic: ~90%
Moderat: 80-60%
Sever: <50%
Supraviatuire Ψcell of -11.5 MPa
Activitate fotosintetica – 5.0 to -8.0 MPa
Creosote Bush:
Larrea tridentata
Saguaro
Stress
abiotic
aclimatizarea
Mojave desert star
Rezistenta
- evitare
- toleranta
Mojave desert star
Impatiens capensis
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SLA (specific leaf area)
Suprafata foliara/ substanta uscata
Desertice (xeric): 0.02 - 0.12
Paduri uscate: 0.36 - 0.70
Mezofite: 1.4 -1.6
Dissected leaves in Palo Verde
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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Raporta sistem radicular/parte aeriana:
Paduri temparate: ~0.25
savana ~0.3 – 0.4
desert~0.6-0.9
Micoriza creste volumul radicular
of growth
Tipul salbatic si mutante ABA-deficient de porumb
cultivate in conditii normale si deficitare de apa
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Leaves of young cotton plants abscise in response to water stress
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cADPR – cyclic ADP-ribose
ROS – reactive
oxygen species
R – Receptor
IP3 – inositol triphosphate
NO – Nitric oxide
PA – Phosphopatidic
acid
PLC – phospholipase D
S1P – Spingosine-1Phosphate
PLC – phospholipase C
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Efectul deficitului hidric asupra cresterii
frunzelor si a ratei fotsintezei la floarea soarelui
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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
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measure of rate of assimilate translocation.
A =gs ( Ca-Ci)
A =gm (Ci-Cc)
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O2
3P680*
3O
2
•O2–
SOD
H2O2
SOD –
Superoxide Dismutase
1O *
2
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Chl – chlorophyll
1Chl* – excited singlet chlorophyll
3Chl* – excited triplet chlorophyll
Demmig-Adams & Adams III
2000 Nature 403: 371
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 16
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
Enzymes：
1) SOD（superoxide dismutase)
2) POD (AscorbatPeroxidase)
3) CAT (Catalase)

Oxidants：
1)
2)
3)
4)
5)
carotene
Vit E
Vit C
GSH
phenolics