Vapour pressure deficit modulates hydraulic function and structure of tropical rainforests under nonlimiting soil water supply
New Phytologist,
Journal Year:
2023,
Volume and Issue:
240(4), P. 1405 - 1420
Published: Sept. 14, 2023
Atmospheric
conditions
are
expected
to
become
warmer
and
drier
in
the
future,
but
little
is
known
about
how
evaporative
demand
influences
forest
structure
function
independently
from
soil
moisture
availability,
fast-response
variables
(such
as
canopy
water
potential
stomatal
conductance)
may
mediate
longer-term
changes
response
climate
change.
We
used
two
tropical
rainforest
sites
with
different
temperatures
vapour
pressure
deficits
(VPD),
nonlimiting
supply,
assess
impact
of
on
ecophysiological
structure.
Common
species
between
allowed
us
test
extent
which
composition,
relative
abundance
intraspecific
variability
contributed
site-level
differences.
The
highest
VPD
site
had
lower
midday
potentials,
conductance
(gc
),
annual
transpiration,
stature,
biomass,
while
transpiration
rate
was
less
sensitive
VPD;
it
also
height-diameter
allometry
(accounting
for
51%
difference
biomass
sites)
higher
plot-level
wood
density.
Our
findings
suggest
that
increases
VPD,
even
absence
limitation,
influence
variables,
such
potentials
gc
,
potentially
leading
stature
resulting
reductions
biomass.
Language: Английский
Assessing the agreement between the pneumatic and the flow‐centrifuge method for estimating xylem safety in temperate diffuse‐porous tree species
Plant Biology,
Journal Year:
2023,
Volume and Issue:
25(7), P. 1171 - 1185
Published: Sept. 13, 2023
The
increasing
frequency
of
global
change-type
droughts
has
created
a
need
for
fast,
accurate
and
widely
applicable
techniques
estimating
xylem
embolism
resistance
to
improve
forecasts
future
forest
changes.
We
used
data
from
12
diffuse-porous
temperate
tree
species
covering
wide
range
safety
compare
the
pneumatic
flow-centrifuge
method,
two
rapid
methods
constructing
vulnerability
curves.
evaluated
agreement
between
parameters
estimated
with
both
sensitivity
measurements
duration
air
discharge
(AD)
measurements.
There
was
close
water
potentials
at
50%
discharged
(PAD),
Pneumatron,
loss
hydraulic
conductivity
(PLC),
method
(mean
signed
deviation:
0.12
MPa,
Pearson
correlation:
0.96
after
15
s
gas
extraction).
However,
relationship
slopes
more
variable,
resulting
in
lower
potential
12%
88%
PAD/PLC.
not
affected
by
species-specific
vessel
length
distributions.
All
were
sensitive
AD
time.
Overall
highest
relatively
short
times,
an
optimum
16
s.
Our
results
highlight
value
Pneumatron
as
easy
reliable
tool
estimate
thresholds
angiosperms.
Further,
our
study
provides
set
useful
metrics
methodological
comparisons
curves
terms
systematic
random
deviations,
well
overall
agreement.
Language: Английский