129 research outputs found
Effects of salinity and drought on growth, ionic relations, compatible solutes and activation of antioxidant systems in oleander (Nerium oleander L.)
[EN] Nerium
oleander
is an
ornamental
species
of high
aesthetic
value,
grown
in arid
and
semi-
arid
regions
because
of its
drought
tolerance,
which
is also
considered
as
relatively
resistant
to salt;
yet
the
biochemical
and
molecular
mechanisms
underlying
oleanderÂżs
stress
toler-
ance
remain
largely
unknown.
To
investigate
these
mechanisms,
one-year-old
oleander
seedlings
were
exposed
to 15
and
30
days
of treatment
with
increasing
salt
concentratio
ns,
up
to 800
mM
NaCl,
and
to complete
withholding
of irrigation;
growth
parameters
and
bio-
chemical
markers
characteristic
of conserved
stress-response
pathways
were
then
deter-
mined
in stressed
and
control
plants.
Strong
water
deficit
and
salt
stress
both
caused
inhibition
of growth,
degradation
of photosynthetic
pigments,
a slight
(but
statistically
signifi-
cant)
increase
in the
leaf
levels
of specific
osmolytes,
and
induction
of oxidative
stressÂżas
indicated
by
the
accumulation
of malondialdehyde
(MDA),
a reliable
oxidative
stress
marker
Âżaccompanied
by
increases
in the
levels
of total
phenolic
compounds
and
antioxidant
fla-
vonoids
and
in the
specific
activities
of ascorbate
peroxidase
(APX)
and
glutathione
reduc-
tase
(GR).
High
salinity,
in addition,
induced
accumulation
of Na
+
and
Cl
-
in roots
and
leaves
and
the
activation
of superoxide
dismutase
(SOD)
and
catalase
(CAT)
activities.
Apart
from
anatomical
adaptations
that
protect
oleander
from
leaf
dehydration
at moderate
levels
of
stress,
our
results
indicate
that
tolerance
of this
species
to salinity
and
water
deficit
is based
on
the
constitutive
accumulation
in leaves
of high
concentratio
ns
of soluble
carbohydrates
and,
to a lesser
extent,
of glycine
betaine,
and
in the
activation
of the
aforementioned
antiox-
idant
systems.
Moreover,
regarding
specifically
salt
stress,
mechanisms
efficiently
blocking
transport
of toxic
ions
from
the
roots
to the
aerial
parts
of the
plant
appear
to contribute
to a
large
extent
to tolerance
in
Nerium
oleanderThis work was financed by internal funds of the Polytechnic University of Valencia to Monica Boscaiu and Oscar Vicente. Dinesh Kumar’s stay in Valencia was financed by a NAMASTE fellowship from the European Union, and Mohamad Al Hassan was a recipient of an Erasmus Mundus pre-doctoral scholarship financed by the European Commission (Welcome Consortium).Kumar, D.; Al Hassan, M.; Naranjo Olivero, MA.; Agrawal, V.; Boscaiu, M.; Vicente, O. (2017). Effects of salinity and drought on growth, ionic relations, compatible solutes and activation of antioxidant systems in oleander (Nerium oleander L.). PLoS ONE. 12(9). doi:10.1371/journal.pone.0185017Se018501712
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