Phases of crown-gall transformation susceptible to hydroxyurea

Abstract

With the use of bacterial strains, both sensitive and resistant to hydroxyurea the action of this inhibitor on tumour formation on the leaves of Kalanchoe daigremontiana infected with Agrobacterium tumefaciens was tested for five days after inoculation. The results are in agreement with the opinion that the anti-tumour effect of hydroxyurea applied in the induction phase (between 18 and 60 h after inoculation) is the result of its direct action on plant cells, whereas inhibition of tumour formation by the inhibitor in the inoculation period depends on its action on the pathogenic bacteria.