Initial anatomical changes associated with tuber formation on single-node potato (Solanum tuberosum L.) cuttings:: A re-evaluation

Cell division and cell expansion during early stages of tuber tuber development were studied using developing axillary buds on single-leaf cuttings from potato (Solanum tuberosum L.). Cuttings taken from plants induced to form tubers, by short day (SD) treatment, were compared with cuttings from non-induced (long day, LD) plants. In the apical zone of the buds, cell division occurred From the first day after cutting, in both LD and SD cuttings. The planes of these divisions were transverse, associated with elongation of the buds. At day 5, a new orientation of cell division was observed in the subapical zone of SD cuttings only. These divisions were longitudinal, associated with radial growth. Cell expansion occurred in both SD and LD cuttings, and was not uniquely related to the onset of tuber formation. (C) 1999 Annals of Botany Company.