Global Change Biology,
Год журнала:
2024,
Номер
30(8)
Опубликована: Авг. 1, 2024
Abstract
Heatwaves
and
soil
droughts
are
increasing
in
frequency
intensity,
leading
many
tree
species
to
exceed
their
thermal
thresholds,
driving
wide‐scale
forest
mortality.
Therefore,
investigating
heat
tolerance
canopy
temperature
regulation
mechanisms
is
essential
understanding
predicting
vulnerability
hot
droughts.
We
measured
the
diurnal
seasonal
variation
leaf
water
potential
(Ψ),
gas
exchange
(photosynthesis
A
net
stomatal
conductance
g
s
),
(
T
can
(leaf
critical
crit
safety
margins
TSM,
i.e.,
difference
between
maximum
)
three
oak
forests
along
a
latitudinal
gradient
Quercus
petraea
Switzerland,
ilex
France,
coccifera
Spain)
throughout
growing
season.
Gas
Ψ
of
all
were
strongly
reduced
by
increased
air
drying,
resulting
closure
inhibition
photosynthesis
Q.
when
surpassed
30°C
moisture
dropped
below
14%.
Across
seasons,
was
mainly
above
but
(up
10°C
>
null
or
negative.
Although
trees
endured
extreme
42°C),
positive
TSM
maintained
during
season
due
high
(average
54.7°C)
possibly
decoupling
(i.e.,
≤0
while
>0).
Indeed,
low
(despite
decreasing
passed
embolism
thresholds.
This
may
have
prevented
from
rising
heat.
Overall,
our
work
highlighted
that
behind
include
combination
evaporative
cooling,
large
limits,
decoupling.
These
processes
must
be
considered
accurately
predict
plant
damages,
survival,
mortality
heatwaves.
Plant Cell & Environment,
Год журнала:
2024,
Номер
47(9), С. 3428 - 3446
Опубликована: Апрель 11, 2024
Changes
in
leaf
temperature
are
known
to
drive
stomatal
responses,
because
the
leaf-to-air
water
vapour
gradient
(Δw)
increases
with
if
ambient
pressure
is
held
constant,
and
stomata
respond
changes
Δw.
However,
direct
response
of
(DRST;
when
Δw
constant
by
adjusting
humidity)
has
been
examined
far
less
extensively.
Though
meagre
available
data
suggest
usually
positive,
results
differ
widely
defy
broad
generalisation.
As
a
result,
little
about
DRST.
This
review
discusses
current
state
knowledge
DRST,
including
numerous
hypothesised
biophysical
mechanisms,
potential
implications
for
plant
adaptation,
possible
impacts
DRST
on
plant-atmosphere
carbon
exchange
changing
climate.
Plant Cell & Environment,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 5, 2025
Functional
redundancy
is
considered
a
pivotal
mechanism
for
maintaining
the
adaptability
of
species
by
preventing
loss
key
functions
in
response
to
dehydration.
However,
we
still
lack
comprehensive
understanding
leaf
hydraulic
systems
along
aridity
gradients.
Here,
photosynthesis
(A
Summary
Plants
integrate
environmental
stimuli
to
optimize
photosynthesis
vs
water
loss
by
controlling
stomatal
apertures.
However,
responses
temperature
elevation
and
the
underlying
molecular
genetic
mechanisms
remain
less
studied.
We
developed
an
approach
for
clamping
leaf‐to‐air
vapor
pressure
difference
(VPD
leaf
)
fixed
values,
recorded
robust
reversible
warming‐induced
opening
in
intact
plants.
analyzed
of
mutants
impaired
guard
cell
signaling
pathways
blue
light,
abscisic
acid
(ABA),
CO
2
,
temperature‐sensitive
proteins,
Phytochrome
B
(phyB)
EARLY‐FLOWERING‐3
(ELF3).
confirmed
that
phot1‐5/phot2‐1
leaves
lacking
blue‐light
photoreceptors
showed
partially
reduced
opening.
Furthermore,
ABA‐biosynthesis,
phyB,
ELF3
were
not
essential
warming
response.
Strikingly,
Arabidopsis
(dicot)
Brachypodium
distachyon
(monocot)
sensors
mechanisms,
including
ht1
mpk12/mpk4‐gc
cbc1/cbc2
abolished
response,
suggesting
a
conserved
mechanism
across
diverse
plant
lineages.
Moreover,
rapidly
stimulated
photosynthesis,
resulting
reduction
intercellular
(CO
).
Interestingly,
further
enhancing
heat
stress
caused
uncoupled
from
photosynthesis.
provide
physiological
evidence
response
is
triggered
increased
assimilation
sensing.
Additionally,
increasing
functions
via
distinct
photosynthesis‐uncoupled
pathway.
New Phytologist,
Год журнала:
2024,
Номер
244(4), С. 1275 - 1287
Опубликована: Авг. 28, 2024
Summary
Climate
change
not
only
leads
to
higher
air
temperatures
but
also
increases
the
vapour
pressure
deficit
(VPD)
of
air.
Understanding
direct
effect
VPD
on
leaf
gas
exchange
is
crucial
for
precise
modelling
stomatal
functioning.
We
conducted
combined
and
online
isotope
discrimination
measurements
four
common
European
tree
species
across
a
range
0.8–3.6
kPa,
while
maintaining
constant
without
soil
water
limitation.
In
addition
applying
standard
assumption
saturated
inside
leaves
(
e
i
),
we
inferred
from
oxygen
CO
2
vapour.
desaturated
progressively
with
increasing
VPD,
consistently
species,
resulting
in
an
intercellular
relative
humidity
as
low
0.73
±
0.11
at
highest
tested
VPD.
Assuming
saturation
overestimated
extent
reductions
conductance
mole
fraction
response
compared
calculations
that
accounted
unsaturation.
addition,
significant
decrease
mesophyll
occurred
when
unsaturation
was
considered.
suggest
possibility
unsaturated
should
be
overlooked
related
models,
especially
high
Agricultural Water Management,
Год журнала:
2024,
Номер
299, С. 108888 - 108888
Опубликована: Май 23, 2024
Due
to
global
warming,
high
temperature
stress
severely
impacts
maize
growth
and
development,
especially
during
the
early
filling
stage.
Supplemental
irrigation
is
an
effective
measure
mitigate
in
maize.
However,
underlying
mechanism
for
alleviating
transient
grain-filling
stage
still
unclear.
A
two-year
field
experiment
involving
(HT),
supplemental
under
(HTW),
control
condition
(W),
treatment
(CK)
by
using
heat-tolerant
variety
ZD958
heat-sensitive
XY335
was
conducted.
Compared
with
CK
treatment,
HT
significantly
decreased
activities
of
superoxide
dismutase
(SOD),
peroxidase
(POD),
catalase
(CAT).
also
reduced
Pn,
soluble
sugar
content
stem,
dry
matter
accumulation,
thus
reducing
kernel
number
per
ear
yield
11.2–17.6%
23.4–23.7%
both
variety,
respectively.
compared
HT,
HTW
daily
mean
canopy
2.6
°C
2.8
°C,
Accordingly,
increased
SPAD
value,
photosynthetic
performance,
starch
sugars
stems
leaves,
antioxidant
enzymes
activities,
but
malondialdehyde
(MDA).
Moreover,
grain
sink
capacity,
prolonged
days
1.4–6.5
d,
average
rate
14.8–41.0%
HT.
Finally,
15.8–22.3%
Therefore,
could
effectively
enhanced
heat
resistance
reduce
temperature.
This
study
provides
important
insights
into
enhancing
stability
a
warming
climate.
Biogeosciences,
Год журнала:
2025,
Номер
22(3), С. 785 - 789
Опубликована: Фев. 12, 2025
Abstract.
A
parsimonious
model
based
on
Dalton's
law
reveals
substomatal
cavities
to
be
dilute
in
oxygen
(O2),
despite
photosynthetic
O2
production.
Transpiration
elevates
the
partial
pressure
of
water
vapour
but
counteractively
depresses
pressures
dry
air's
components
–
proportionally
including
preserving
cavity
pressurization
that
is
negligible
as
regards
air
composition.
Suppression
by
humidification
overwhelms
enrichment,
reducing
molar
fraction
inside
cool
or
warm
leaves
hundreds
thousands
parts
per
million.
This
elucidates
mechanisms
realize
transport:
diffusion
cannot
account
for
up-gradient
conveyance
from
through
stomata
more
aerobic
atmosphere.
Rather,
leaf
emissions
depend
non-diffusive
transport
via
mass
flow
forced
pressurization,
which
not
context
dynamics.
Non-diffusive
expulsion
overcomes
massive
inward
force
net
emission.
At
very
high
temperatures,
also
influences
and
carbon
dioxide,
physically
decoupling
their
exchanges
water-use
efficiency,
independently
stomatal
regulation.
