Transformation tumorale chez le pois: passage d'un état précancéreux à l'état cancéreux

Abstract

Decapitated pea stems were infected by bacteria from virulent strains of Agrobacterium tumefaciens, sensitive or resistant to streptomycin, actinomycin, or rifampicin, and the antiobiotics were added at the same time as bacteria. At the concentrations used, they have no toxic action on plants. The determination of the number of ‘viable’ bacteria allowed us to describe a kinetic of the development of the bacterial population in vivo in relation to the inhibition of the continuous proliferation of the hyperplasia. The histological study agrees with this and allows the definition of two steps during the tumorous induction: the first one results in the formation of a callus with a limited growth (precancerous state), while the second is the maintenance of the anarchic and unlimited multiplication of the converted host cells (cancerous state).