Wohlfahrt, Y., Smith, J.P.,
Tittmann, S., Honermeier, B.
and Stoll, M.
2018
Primary
productivity
and
physiological
responses
of Vitis Vinifera L. cvs.
Under Free Air
Carbon dioxide
Enrichment
(FACE).
European Journal
of Agronomy 101: 149-162.
NOTE:
Viticulture
( growing grapes
for making wine )
is a key industry
in many parts
of the world.
Wohlfahrt et al. (2018)
used FACE
technology
to examine two
key cultivars
to a small
( +79 ppm )
increase in the
CO2 concentration
over three
consecutive
growing seasons
( 2014 - 2016 ).
SUMMARY:
A small
( +79 ppm )
increase in
atmospheric
CO2 is capable
of providing
such significant
growth benefits.
Wohlfahrt et al. report:
"the elevated CO2
treatment led to
significantly higher
net assimilation
as well as intrinsic
water use efficiency,
evaporation and
stomatal conductance
for both cultivars."
The sugar
concentration
of must at harvest
were not affected
by elevated CO2
for either grape
variety.
Eelevated CO2
"resulted in higher
total yield and
clean fruit yield"
( clean fruit yield
is the total yield
minus fruit infected
with bunch rot
caused by Botrytis
cinerea ).
Clean fruit yield
was enhanced by
a three-year average
of +7.5% for Riesling
and 11.2% for
Cabernet Sauvignon.
They note that
"neither incidence
nor frequency
of B. cinerea
was altered under
elevated CO2
for both cultivars."
DETAILS:
The plants
were grown
in the field at the
VineyardFACE
experimental site
at Hochschule
Geisenheim
University
in the Rheingau
wine region
of Germany.
CO2 fumigation
in the elevated
CO2 treatments
was applied during
daylight hours only
for all days
of the year.
Riesling was selected
"as a representative
of a white cool climate
cultivar having
a long tradition
of cultivation
in Germany,"
Cabernet Sauvignon,
was selected
"as a warmer
climate cultivar
and one of the
most renowned
and widely grown
red grape varieties
in the world."
A number of
physiological and
growth-related
measurements
were collected\
to determine
the impacts
of elevated CO2
during the
three year study.
CHARTS BELOW
Net photosynthesis
increased by
+17%, +40% and +40%
for Riesling, and by
+12%, +30% and +43%
for Cabernet Sauvignon
in 2014, 2015, and 2016,
respectively.
A decline
in stomatal
conductance,
led to an average
+10% and +21%
increase in intrinsic
water use efficiency
for Cabernet Sauvignon
and Riesling cultivars,
respectively, over the
three-year study period.
Net photosynthesis (A)
and intrinsic water
use efficiency (WUEi)
of Vitis vinifera cultivars
Riesling and
Cabernet Sauvignon
grown under ambient
( yellow shaded bars )
and elevated
( blue shaded bars )
CO2 for three
growing seasons.
Means and standard
errors are shown and
*** indicates statistical
significance (p < 0.001)
of main factor treatment
over three years.
