02115nas a2200157   4500008004100000245011400041210006900155300001300224490000700237520151900244100002001763700001701783700001501800700001701815856012501832       1988                        eng d00aEffects of soil microorganisms on mycorrhizal contribution to growth of big bluestem grass in nonsterile soil0 aEffects of soil microorganisms on mycorrhizal contribution to gr  a501 -5070 v203 a<p>Plant dry weight and mycorrhizal root colonization of big bluestem (Andropogon gerardii Vitman) inoculated with Glomus etunicatum Becker and Gerd. were suppressed if non-sterile prairie soil sievings were added to pasteurized soil. Addition of prairie soil microorganisms, isolated onto peptone yeast extract, King&#39;s B, or starch casein agar media, to pasteurized soil also reduced dry weight and mycorrhizal root colonization of big bluesteam inoculated with G. etunicatum. In contrast, addition of non- sterile soil sievings or filtrate or organisms isolated onto potato dextrose or pseudomonas isolation agar to pasteurized soil improved growth of non-mycorrhizal big bluestem. These effects of soil microorganisms on plant growth were further quantified by comparing 32P uptake by fungicide treated and untreated mycorrhizal plants and by non-mycorrhizal plants in pasteurized and non-sterile soil. Mycorrhizal plants grown in pasteurized soil absorbed approximately 10 times more 32P than mycorrhizal plants grown in non-sterile soil. Application of propiconazole (Tilt) or fenarimol (Rubigan), fungicides which inhibit non-sterile soil, respectively. Thus, more 32P is absorbed in pasteurized than in non-sterile soil, probably because soil microorganisms limit mycorrhizal activity in non-sterile soil. Assessments of mycorrhizal contribution to plant growth conducted in sterilized soil may significantly overestimate the effects of VAM fungi because other soil microorganisms are not considered</p>1 aHetrick, B.A.D.1 aWilson, G.T.1 aKitt, D.G.1 aSchwab, A.P.  uhttp://knz.lternet.edu/content/effects-soil-microorganisms-mycorrhizal-contribution-growth-big-bluestem-grass-nonsterile