AMYLOPLAST FORMATION IN CULTURED TOBACCO CELLS - EFFECTS OF PLANT HORMONES ON MULTIPLICATION, SIZE, AND STARCH CONTENT

In BY-2 cultured tobacco cells (Nicotiana tabacum L), depletion of 2,4 -dichlorophenoxyacetic acid (2,4-D) and addition of benzyladenine (BA) caused amyloplast formation, a decrease in cell multiplication, and a n increase in cell size, These changes were primarily triggered by the depletion of 2,4-D, and facilitated by the addition of BA. An increas e in the starch content of BY-2 cells was always accompanied by a redu ction in cell multiplication. However, when hormonal conditions were u nsuitable for amyloplast formation, the starch content of the cells di d not increase, even ii cell multiplication was forcibly terminated by ;he addition of aphidicolin. This result indicates that the hormonal c onditions themselves, and not the decrease in cell multiplication, ind uce amyloplast formation in BY-2 cultured tobacco cells.