THE COMPARATIVE GROWTH OF BACTERIAL ISOLATES FROM RHIZOSPHERE AND NON-RHIZOSPHERE SOILS

Abstract

The growth response of bacterial isolates from the rhizosphere of greenhouse and field crops and control soils was studied in media of increasing complexity. In general, a greater proportion of rhizosphere isolates from the greenhouse crops grew more abundantly than did those from non-rhizosphere soils. This was not evident in all cases with the field crops. The addition of root extracts to an already complex medium did not result in growth stimulation. In fact the extract from oat roots was decidedly inhibitory to both rhizosphere and soil isolates.