The aim of the present study was to determine
whether arbuscular mycorrhizal (AM) inoculation with a
biofertilizer containing clays as granular carriers, leek root
pieces and Glomus intraradices spores could improve
alkalinity tolerance of two cucumber genotypes, and to
study the changes induced by AM at agronomical and
physiological level. A greenhouse experiment was carried
out to determine yield, growth, fruit quality, net photosynthesis
(ACO2), electrolyte leakage, and mineral composition
of two cucumber (Cucumis sativus L.) genotypes (hybrid
“Ekron” or open-pollinated variety “Marketmore”) with
inoculated and noninoculated arbuscular mycorrhizal biofertilizer.
Plants were supplied with nutrient solutions at
two pH values (6.0 or 8.1). The high pH nutrient solution
had the same basic composition with an additional 10 mM
NaHCO3 and 0.5 gl−1 CaCO3. The percentage root
colonization was higher in “Marketmore” (21.8%) than
“Ekron” (12.7%). Total and marketable yield and total
biomass were significantly higher by 189%, 213%, and
77%, respectively, with Ekron in comparison to those
recorded with Marketmore. The highest crop performance
with Ekron in comparison to Marketmore was due to the
improved nutritional status (higher N, P, K, Ca, Mg, Fe,
Mn, and B), higher leaf area, and net photosynthesis.
Increasing the concentration of NaHCO3 from 0 to 10 mM
in the nutrient solution significantly decreased yield, plant
growth, ACO2, N, P, Fe, Cu, Zn, Mn, and B concentration in
leaf tissue, whereas the electrolyte leakage increased. The
inoculated plants under alkaline conditions had higher total,
marketable yield, and total biomass than noninoculated
plant. Mycorrhizal cucumber plants grown under alkaline
conditions had a higher macronutrient concentration in leaf
tissue compared to noninoculated plants. The highest yield
and biomass production in inoculated plants seems to be
related to the capacity of maintaining higher net ACO2 and
to a better nutritional status (high P, K, Mg, Fe, Zn, and Mn
and low Na accumulation) in response to bicarbonate stress
with respect to −AM plants
