GROWTH OF THE SHOOT APEX OF AGROPYRON-REPENS (L) BEAUV DURING SUCCESSIVE PLASTOCHRONS

Two kinds of size change occur in the apical dome of Agropyron repens during development of the shoot. A cyclic increase and decrease in size results from the production of a new stem segment and associated leaf primordium during each plastochron. A progressive increase and then decrease in size, which occur over a period of several plastochrons, is attributable to discrepancies between the size increment during each plastochron and the size of the stem segment formed at the end of the plastochron. The volume doubling time of the dome remains constant at approximately one plastochron. Fluctuations in mean cell generation time correlate with changes in mean cell volume and do not contribute to the size changes of the dome. © 1979, Annals of Botany Company.