THE INITIATION OF THE RHIZOSPHERE MYCOFLORA OF DWARF BEAN PLANTS

An attempt was made, using the soil-washing box technique, to obtain detailed information about the initiation of the rhizosphere mycoflora of dwarf bean seedlings.Tabulated information of the fungi isolated from washed non-rhizosphere soil and washed rhizosphere soil from plants during the first 20 days after seed germination is presented together with data of the fungi isolated from the waters in which these soil samples were washed. These data are discussed in relation to previous observations of fungi isolated from rhizospheres by other methods.The results obtained revealed that in the early days after seed germination the rhizosphere mycoflora was qualitatively similar to that of the non-rhizosphere soil. However, a number of distinct differences were discernible between the rhizosphere and non-rhizosphere populations even at these early stages of plant growth, namely that Cylindrocarpon radicicola, Humicola grisea, and a sterile sclerotial form (W1) were isolated with increased frequency from the rhizosphere, whereas Trichoderma viride was consistently isolated less frequently from the rhizosphere than from non-rhizosphere soil.