Anther-filament Extension in Lilium: Potassium Ion Movement and Some Anatomical Features

The growth of the anther filaments in the Lilium bud is essentially exponential after a length of 5 mm is reached, when the cell division rate declines and growth is by cell extension, particularly of cells in the central part of the filament. During the period of extension, fresh vascular tissue is formed and xylem continuity is conserved up to the time of anther dehiscence, in contrast to the Graminae where the filament extends much more rapidly. The expansion of the lily filament depends in part on the continuous transfer of potassium ions from the receptacle throughout the period of growth. Although starch to sugar conversion may be an important source of osmoticum as the cells expand, regulation of K⁺ ion movement would be likely to provide a more sensitive and faster method of regulation of cell osmoticum.