Azotobacter chroococcum in the Aerial Roots of the Banyan Tree

Abstract

OTHER workers have reported mixed bacterial flora in healthy plant parts such as stems, taproots and storage organs of potato, lucerne, turnip and sweet clover^1,2. These mixed flora differ in their size and in the reaction to Gram stain. One of these isolates commonly present in the older potato stems was identified as Bacterium radiobacter by Dr. A. G. Lochhead. Hennig and Villforth³ investigated twenty-eight different healthy plants and found bacteria in all parts (leaves, twigs, stems and roots of all plants at all stages). Marcus⁴ cultured the inner sound tissue of seeds and fruits of a number of different plants and obtained fungi, yeasts or bacteria from some kinds but found others sterile. The presence of an Azotobacter sp. in the swollen roots of Cyperus rotundus has been reported⁵. During an investigation of the aerial roots of banyan trees it was found that Azotobacter chroococcum capable of fixing atmospheric nitrogen when cultured on the nitrogen-free medium of Jensen⁶ occurred in the interior of the roots.