LynchJ.M.&ClarkSarahJ. 1984. Ejects of microbial colonization of barley (Hordeum vulgareL.) roots on seedling growth.Journal of Applied Bacteriology56, 47–52.A range of micro‐organisms, particularly pseudomonads, was isolated from seed, rhizosphere soil and straw. Their colonization and effects on the growth of barley seedlings in gnotobiotic culture were studied. The colonization potentials of the different species were between 004 and 47 times 106viable cells/mg dry root. Some organisms stimulated root and shoot extension and dry matter production while others were inhibitory; these effects were not directly related to the colonization potenti