Nucleic acids and tumor genesis in broad bean.

In an earlier communication, marked changes were reported in the level of nucleic acids during structurally well defined stages in the genesis of crown gall tumors in tomato (9). In view of the distinctive pattern of these changes, it seemed ad visable to extend these studies to other plant tumors to ascertain whether nucleic acid changes were, in fact, concurrent with the process of tumorigenesis and to determine whether they were related to the histological and cytochemical changes that occur in tumor genesis. Furthermore, it was important to determine whether these changes were restricted to tumors or were charac teristic of plant neoplastic growth in general. Broad bean (Vicia f aba, var. English Windsor) was chosen for this study, to compare earlier studies on Agrobacterium tumefaciens tumors in tomato with a different host and pathogen. The bean is not susceptible to A. tumefaciens, but when inoculated with A. rubi does form tumors which are grossly distinct from those formed by tomato and many other hosts (4). Furthermore, bean tissues possess large cells and nuclei which can be studied histochemically.