PHYSIOLOGICAL AND ULTRASTRUCTURAL STUDIES ON TUMORIZED CELLS OF SUNFLOWER PLANTS

Abstract

Many spec1es of higher plants, most dicotyledonous plants, are susceptible to crown-gall disease. This disease is characterized by the formation of tumours, as a result of infection of wounded sites by gram-negative soil bacteria (Agrobacterium tumefaciens). In fact, sterile crown-gall tissues can readily be cultured indefinitely on simple media lacking any added growth hormones.

The present work was carried out to study the biochemical and ultrastructural differences in crown-gall of stem tissues when compared with normal tissues.

On the other hand these biochemical differences were studied in isolated crown-gall tumour grown on axenic media when compared with normal calli at different growth stages.

The main experimental results can be briefly sununarised in the following :

1- The use of antibiotic on isolation of bacteria-free tumour, velosief antibiotic at

100!-!g/rnl was added on MS media to kill bacteria. After several subculturing on MS hormone-free media with velosief antibiotic, these tissues were able to grow on MS media without antibiotic. 2- In tumorized tissue, auxins and cytokinins have increased as compared with normal stem and normal calli. 3- Pol¥amines contents (Putrescine, Spermine Spermidine and Cadaverine) were increased in tumorized tissues as compared with normal tissues. 4- Lipid fractions such as phospholipid, neutral and total lipids, highly significantly increased in tumorized tissue as compared with normal tissues of stem and calli tissue.