Production of adventitious root primordia on hypocotyls of castor bean seedling, infected with Agrobacterium tumefaciens.

The development of sterile secondary tumours on hypocotyls of castor bean seedlings, inoculated with any of the ten isolates of Agrobacterium tumefaciens tested, were observed below the site of the primary tumours. Histopathological studies performed in the present work indicate that the observed secondary tumours were adventitious root primordia and not the ordinary type of secondary tumours. According to the available literature such findings are reported here for the first time. All the tested isolates of the present study were also able to initiate well defined roots in conjunction with crown gall (teratomas) on Bryophyllum crenata and Kalanchoe marmorata, but not in tomato.