Influence of bacteria on growth and phosphorus nutrition of mycorrhizal corn

Com plants were grown in a non‐sterile soil in a greenhouse or in hydroponic culture in a growth chamber. We studied the influence of chitinolytic, pectinolytic, P‐solubilizing bacterial isolates, and a collection of bacterial strains on the development of native vesicular‐arbuscular mycorrhizal (VAM) populations, colonization of roots by the VAM fungus Glomus fasciculatum and their influence on the phosphorus (P) nutrition and growth of plants. As compared with VAM native control, the most potent stimulants for root colonization of soil‐grown plants by the VAM native population was a strain of Agrobacterium radiobacter and isolate H30. All bacteria used significantly supressed shoot fresh weight of mycorrhizal plants (‐13% up to ‐37%), with the exception of Agrobacterium. Under hydroponic conditions, the P‐solubilizing isolate F27 significantly stimulated the intensity of mycorrhiza, the number of arbuscules in roots, and increased both the P concentration and P content in corn shoots (+30% and +35%), than did the VAM fungus alone. Isolate F27 significantly increased shoot dry weight as compared with the mycorrhizal control. The other bacteria did not influence biomass production of corn.