INFLUENCE OF BACTERIA ON GROWTH AND PHOSPHORUS-NUTRITION OF MYCORRHIZAL CORN

Corn plants were grown in a non-sterile soil in a greenhouse or in hyd roponic culture in a growth chamber. We studied the influence of chiti nolytic, pectinolytic, P-solubilizing bacterial isolates, and a collec tion of bacterial strains on the development of native vesicular-arbus cular mycorrhizal (VAM) populations, colonization of roots by the VAM fungus Glomus fasciculatum and their influence on the phosphorus (P) n utrition and growth of plants. As compared with VAM native control, th e most potent stimulants for root colonization of soil-grown plants by the VAM native population was a strain of Agrobacterium radiobacter a nd 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 c ontent 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.