Morphogenesis in Cell Colonies Grown From Convolvulus Cell Suspensions Plated on Synthetic Media

Filtered cell suspensions of cultured callus tissue derived from the roots of Convolvulus arvensis L. were plated out on synthetic agar nutrient media in petri plates. Cell colonies which formed from the single cells or small cell groups in the suspension showed a considerable range of developmental patterns depending upon the physical and chemical environment to which they were exposed. Variation of the auxin and kinin concentrations and the nature and concentration of the source of reduced N compounds had the most profound effects on colony development. High auxin favored cell enlargement, high kinin favored the development of compact colonies composed of many small cells. Both auxin and kinin were required for cell colony formation. Cell differentiation responses which were observed but not subject to experimental control included formation of starch‐ and crystal‐storing cells, differentiation of tracheary elements, formation of cellular filaments, and development of chlorophyllous tissue. Organ initiation was studied in cell colonies developed directly from plated cell suspensions and in cell colonies subcultured on various nutrient media. Bud initiation was produced repeatedly on media containing NAA at 10 ‐8 to 10 ‐6 m combined with kinetin at 10 ‐6 m . Root initiation was induced infrequently and unpredictably. Once roots had been formed from cell colonies derived from cell suspensions, the roots could be subcultured and induced to form buds; these in turn grew into whole plants. Subculture of young cell colonies to media containing different combinations of growth substances made possible a study of the effects of auxin and kinin on organization of primordia by the cell colonies. By following marked single cells plated on synthetic media, it was possible to produce single‐cell clones which under proper nutrient conditions were induced to form buds. The value of the combined techniques of cell suspension culture and cell plating for the study of the physical and chemical factors influencing cell differentiation and organized development are pointed out.