Untersuchungen an Crown-Gall / Investigations on Crown-Gall

Abstract

Young leaves of Kalanchoe daigremontiana are hurt with a “hedgehog” (a holder with 30 needles) to produce wounds of equal size in great numbers and definite intervals. Infection of these leaves with suspensions of Agrobacterium tumefaciens, strain B6, results in first small tumors as soon as 7 days after infection. A quantitative evaluation of the experiments is possible 14 days after infection. The number of induced tumors increases linearly with the logarithm of the concentration of the bacteria. The diameter of tumors (21-d-old), too, depends on the concentration of the bacteria. - The tumors mass a product of the relative success of infection I (number of tumors per number of wounds, and the average tumor diameter gives a third measure of the bacteria concentration. An application of this hedgehog-test is given: If the infecting bacteria are treated with lysozyme and EDTA the success of the infection decreases with increasing time of treatment. This decrease is reduced by the presence of 11% sucrose.