Li, X., Kristiansen, K.,
Rosenqvist, E. and Liu, F.
2019
Elevated CO2 modulates
the effects of drought
and heat stress on plant
water relations and
grain yield in wheat.
Journal of Agronomy
and Crop Science 205: 362-371.
NOTE:
This experiment was conducted
at the University of Copenhagen
in Taastrup.
It investigated the
interactive effects
of short-term drought
and heat stress on
two wheat genotypes
(cv. Galdius and Paragon)
growing in pots in
controlled-environment
greenhouses under
two atmospheric
CO2 concentrations
(400 and 800 ppm).
Li et al. report that
"post-anthesis drought
and heat stress
significantly reduced
the grain yield in wheat,
and their combination
exacerbated this
adverse effect".
SUMMARY:
Elevated CO2
will help mitigate
the negative impacts
of post-anthesis
heat and drought stress,
and their combination,
on wheat grain yields.
"Consistent with earlier
studies, a significant increase
in grain yield was found
in plants grown under
elevated CO2, compared with
that under ambient CO2."
The chart below reveals
CO2-induced increases
in grain yield for Gladius
of 20%, 17%, 24% and 18%
under C, D, H and DH treatments.
For Paragon, this cultivar
did not experience any
CO2-induced enhancement
of grain yield under control
conditions, but witnessed
much larger increases of
69%, 34% and 50% due to CO2
in the D, H and DH treatments.
DETAILS:
Shortly after anthesis,
half of the plants in each
CO2 treatment were exposed
to moderate drought
in which the researchers
withheld irrigation for 5 days,
reaching a soil water
content of 16%.
They subjected
half of the pots in each
watering treatment
(moderate drought
or adequate water)
to a simulated heat wave
(day/night temperatures
of 40/35°C compared to
ambient 24/16°C)
for five more days.
There were eight
treatments in total:
Chart Below:
Grain yield (GY)
of two wheat genotypes
(cv. Gladius and Paragon)
at various CO2 levels
(ambient at 400 ppm
or elevated at 800 ppm),
drought (D),
elevated heat (H)
and/or combined drought
and elevated heat (DH).
C, the control;
A, ambient CO2;
E, elevated CO2.
The red text reveals
the percentage
enhancement
in grain yield
due to elevated CO2
for each cultivar
in each stress treatment.
