Introduction: Representatives of the Azotobacteriaceae family are regular inhabitants of soils of roots
(rhizosphere) and on the root surface of free-living nitrogen fixing bacteria of the genera Azotobacter and
Azospirillum. They are the regular associates of the roots of many tropical grasses and cereals. Their
associations with medicinal plants are of paramount importance. The medicinal plants such as Aloe vera
and Datura alba were selected to access the nature of association in the rhizosphere and on the roots by
the above bacteria