Effect of dual inoculation with arbuscular mycorrhizal fungi and bacteria on growth and mineral nutrition of strawberry

Micropropagated plants of Fragaria x ananassa (cv. Senga sengana) were post-vitro inoculated in two experiments with the arbuscular mycorrhizal fungi Glomus fasciculatum, Glomus etunicatum and or Glomus claroideum and with bacterial isolates obtained from plant rhizosphere, from mycorrhizal mycelium and from root-free substrate. In the first experiment, the inoculation with the bacterial isolate M30 (from mycorrhizal mycelium) and with arbuscular mycorrhizal fungi G. fasciculatum and G. etunicatum significantly increased the plant growth. Bacteria frequently stimulated development of mycorrhiza, particularly the growth and dehydrogenase activity of extraradical mycorrhizal mycelium. In the second experiment, the isolate-specific effects of bacteria and mycorrhizal fungi were found at different doses of phosphorus (P) and nitrogen (N). The interaction between nutritional regime. bacteria and the fungi may be a determining factor of mycorrhizal symbiosis efficiency as regards possible benefits in stimulation of plant growth.