Zhang, Y., Dai, Y., Wan, G.,
Liu, B., Xing, G. and Chen, F.
2018
"Effects of elevated CO2
on plant chemistry, growth,
yield of resistant soybean,
and feeding of a target
Lepidoptera pest,
Spodoptera litura
( Lepidoptera: Noctuidae )"
Environmental Entomology 47:
848-856.
SUMMARY
Elevated CO2 stimulated
aboveground biomass,
foliar sugar content and C/N ratio,
leading to soybean seed yield
increases of +16 to +25%
in the Lamar cultivar and
+3-20% in the JLNMH cultivar.
Elevated CO2 caused a reduction
in foliar nitrogen content
of approximately 16% in Lamar
and 9% in JLNMH between
the R4 and R6 growth stages.
Correlation analyses
between foliar chemistry
of the soybean leaves
grown under ambient
and elevated CO2 conditions
and the growth indices
of S. litura revealed that
"high foliar sugar
and low N content,
and high foliar C/N ratio
[negatively impacted]
the growth, development,
and fecundity of S. litura."
The highly insect resistant Lamar cultivar
not only experienced a better yield
performance than the susceptible
JLNMH cultivar under elevated CO2,
it also demonstrated a
"better performance against
herbivorous Lepidoptera insect pests."
In the future, farmers
who grow the Lamar cultivar
might be best able
to take advantage of the
plant yield-enhancing and
pest damage-reducing effects
observed here from
rising atmospheric CO2.
DETAILS
The six Chinese researchers
grew two soybean cultivars
( Lamar and JLNMH ) in pots
in open-top chambers
under ambient (~374 ppm)
or elevated (~732 ppm)
atmospheric CO2 concentrations
for three consecutive
growing seasons
( 2013, 2014 and 2015 ).
Additionally, they reared larvae
of a leaf-chewing herbivorous
insect ( Spodoptera litura )
in a controlled-environment
setting and fed the larvae
with leaves from the two cultivars
grown in the two CO2 treatments.
One of the soybean cultivars (Lamar)
is considered highly resistant
to S. litura attack while the other (JLNMH)
is considered highly susceptible.
