The toxicity of legume seed diffusates toward rhizobia and other bacteria

Summary Seed coat diffusates from the legumesCentrosema pubescens and subterranean clover were found to contain a water-soluble, thermostable, antibiotic inhibiting a wide range of rhizobia and other gram-negative organisms as well as gram-positive organisms. Lucerne seed diffusate showed little activity. The extent of inhibition varied with the micro-organism. Diffusate from subterranean clover was generally more active than fromC. pubescens.It was shown that seed diffusates can have a depressive or a stimulative effect on multiplication of organisms around seeds germinating in sand and soil.The significance of the results, particularly with respect to inoculation with Rhizobium is discussed.