Xu, Q., Fan, N., Zhuang, L.,
Yu, J. and Huang, B.
2018
"Enhanced stolon growth
and metabolic adjustment
in creeping bentgrass
with elevated CO2
concentration"
Environmental and
Experimental Botany
155: 87-97.
NOTE:
Xu et al. noted that
limited information
was available
on the effects of
elevated
atmospheric CO2
concentration
on stolon growth.
Their objective was to obtain
such information on the
perennial grass species
known as creeping bentgrass
( Agrostis stolonifera ).
SUMMARY:
Xu et al.
report that drought
caused a rapid decrease
in plant relative
water content (RWC)
and increased
leaf electrolyte leakage
regardless of
CO2 concentration.
However,
they found that
elevated CO2
"alleviated the adverse effects
of drought on both [of these]
parameters in creeping bentgrass."
Xu et al. say that
"extensive stolon elongation
is a highly desirable trait
for the rapid establishment
and survival from biotic
and abiotic damages
for stoloniferous
grass species."
And they add that:
"the CO2-responsive metabolites
for carbohydrate reserves,
respiratory metabolism,
and membrane maintenance
could contribute to the
enhanced stolon growth,
thereby potentially facilitating
rapid stand establishment
and increasing
shoot biomass
production
in perennial
grass species."
This study suggests future increases
in atmospheric CO2 concentrations
will likely benefit this and other
stoloniferous plant species,
especially during times of drought.
DETAILS:
Xu et al. (2018) write that
"stolons are stems growing
at the soil surface, with
each stolon consisting of
multiple nodes and internodes,
and stolon nodes contain
meristematic tissues
capable of forming
adventitious roots
and daughter plants
from the nodes."
They note that stolons
"are also storage organs
for resources, such as
carbohydrates, mineral
nutrients and water,
providing support
for plant survival
of environmental
stresses."
Stolon development
and growth are, in their words,
"highly desirable characteristics
for stoloniferous plant species,"
including perennial grasses,
which utilize
stoloniferous propagation
or sprigging for rapid
stand establishment.
To accomplish this goal,
the five scientists placed
two-month-old samples
of the grass species
(cv. Alpha)
in controlled-environment
chambers under identical
growing conditions.
After a two-week
acclimation period,
the plants
were subjected to
treatments of
either ambient (400 ppm)
or elevated (800 ppm) CO2 and
well-watered or deficit
(50% of well-watered) i
irrigation conditions
for the next 26 days.
Multiple growth and physiological
measurements were then made
during the course
of the treatment period.
At the end of the 26-day
treatment period, plant RWC
was +37.1% higher and
leaf electrolyte leakage
was -44.5% lower
in the drought treatment
under elevated CO2 conditions
compared to that observed
in ambient CO2, while
no significant differences
between ambient
or elevated CO2
were detected
for these two parameters
under well-watered conditions.
Xu et al. also report that
elevated CO2 enhanced
the growth of stolons,
increasing
"the number of stolon internodes
by +25.8% and +75.6%, and the
stolon length by +35.4%
and 1.01-fold, respectively,
under well-watered control
and drought stress conditions."
Metabolic profiling revealed changes
in several metabolites in the stolons
in response to CO2 enrichment.
In particular,
metabolites involved
with sugar metabolism,
amino acid metabolism,
fatty acid metabolism and
respiratory metabolism
in the stolon nodes were enhanced,
leading the authors to reason that
"the enhanced content
of those metabolites
could contribute to the
stimulation of stolon growth
by elevated CO2."