Zhuang, L., Yang, Z.,
Fan, N., Yu, J. and
Huang, B.
2019
Metabolomic changes
associated with
elevated CO2-regulation
of salt tolerance in
Kentucky bluegrass.
Environmental and
Experimental Botany 165: 129-138.
NOTE:
Excessive accumulation
of sodium in soils
(i.e.; salinity stress)
is harmful to plants.
Elevated levels of
atmospheric CO2
have been shown
to promote plant
growth and alleviate
stresses.
Zhuang et al. studied
the combined effects
of elevated CO2 and
salinity stress on
Kentucky bluegrass
(Poa pratensis cv. Kenblue).
SUMMARY:
Elevated CO2 had
a positive effect
while salinity stress
had a negative effect
on the growth rate and
net photosynthesis.
Zhuang et al. report
"elevated CO2
effectively ameliorated
plant growth and
physiological damages
due to salt stress,
as shown by the
increase in turf quality,
relative water content,
leaf chlorophyll content,
shoot growth rate,
net photosynthetic rate,
and K+ content,
as well as by the
reduction in electrolyte
leakage and Na+ content
in both leaves and roots."
CO2-induced
metabolite changes,
are likely the reason
why elevated CO2
improved the salt
tolerance of this
perennial grass
species.
DETAILS:
Work was conducted
in growth chambers under
controlled environments
over a period of 42 days.
Treatments included
control:
Ambient CO2 concentration
of 400 ppm and 250 mL
of salt-free irrigation
water daily),
Elevated CO2
(elevated CO2
concentration
of 800 ppm
and 250 mL
of salt-free
irrigation daily),
Salt stress
(ambient CO2
and 250 mL
of daily irrigation
water containing
200 mM NaCl solution
to induce salt stress) and
Combined
elevated CO2
and salt stress
(800 ppm CO2
and 250 mL
of daily irrigation
water containing
200 mM NaCl solution).
During each week of the
experiment the researchers
measured a number of
plant growth and physiological
indices to evaluate the impact
of the two variables.
At the end of
the 42 day study
period they sampled
fresh leaves and roots
to determine leaf ion
contents and to extract
and quantify
various metabolites,
hoping to discern
the mechanisms
behind the
physiological changes
observed in their study
Chart below:
Effects of CO2 concentration
on relative shoot growth
(left panel)
and net photosynthetic
(right panel)
rates of Kentucky bluegrass
exposed to salt stress.
The 400 and 800 refer to
ambient (400 ppm)
and elevated (800 ppm)
CO2 concentrations,
respectively.
Vertical bars in the left panel
represent significant difference
between different treatments
based on LSD values (P ≤ 0.05).
Vertical bars in the right panel
indicate standard errors
of the mean for each treatment.
Columns marked with
small letters and *
represent the salt-induced
significant differences at
a given CO2 concentration
and the elevated CO2
-induced significant
differences at either
control or salt stressed
condition, respectively,
based on LSD values
(P ≤ 0.05).
