Pérez-Jiménez, M.,
Piñero, M.C. and
del Amor, F.M.
2019
Heat shock, high CO2
and nitrogen fertilization
effects in pepper plants
submitted to elevated
temperatures.
Scientia Horticulturae 244: 322-329.
NOTE:
Pérez-Jiménez et al. (2019)
examined the combined
impact of elevated CO2
and heat shock at
different levels of
nitrogen supply
on seedlings of an
important agricultural
crop -- sweet pepper
(Capsicum annuum, cv. Herminio),
SUMMARY:
The authors
conclude that
"elevated CO2
and heat action
are two promoters
of plant growth
and development
which,
under climate change,
might suppose also
the avoidance of
increasing drought
and salinity stress
and contamination
of water reserved by N."
And that's good news
for sweet pepper plants
if both temperature
and CO2 levels rise
in the future.
At the end
of the experiment,
"plants grown
at elevated CO2
were markedly taller
and more leafy
than those cultivated
at ambient CO2."
Elevated CO2
also increased
the net rate of
photosynthesis
and the water
use efficiencies
of the seedlings
regardless of
N treatment.
The scientists also report
that high temperature stress
"did not lead to any
measurable stress
in the sweet pepper plants."
In contrast,
because there was
an adequate supply
of water, it
"augmented
photosynthesis"
and other key
physiological
functions.
Pérez-Jiménez et al.
also found that
elevated CO2
"was able
to ameliorate
the damage
in N-starved
plants [under high
emperature stress],
thereby making
a difference
on plant survival."
DETAILS:
The experiment
was conducted in
controlled-environment
chambers with the
CO2 concentration
being maintained
at either ambient
( 400 ppm )
or elevated levels.
( 1000 ppm )
Nitrogen (N) treatments
included nutrient solutions
containing 0, 5 or 12 mM of N.
Additionally,
a fourth N treatment
included 0 mM of N,
but with the addition
of plant growth-promoting
rhizobacteria as a
possible N source
for the pepper seedlings.
Then, after 15 days
under these CO2 and N
treatment conditions,
the researchers
induced heat stress
by raising the
ambient daytime
air temperatures
from 28°C to a
whopping 43°C,
maintaining
the stressful
temperatures
for a full 3 days.
Various
physiological
measurements
taken before and
at the peak
of heat stress
allowed the authors
to witness multiple
beneficial impacts
of elevated CO2 on
the pepper seedlings.
Chart Below:
Effects of heat shock
and elevated CO2
( 1,000 ppm )
on net photosynthesis
( ACO2 )
and water use efficiency
( WUE )
under different
nitrogen treatments
(12 mM, 5 mM,
0mM+PGPR,
0 mM of N)
before (28 °C)
and after
heat shock (43 °C).
Values are means ± SE.
