ABSTRACT
SUMMARY. Dormancy in perennial plants is the phenomenon that growth and development are temporarily suspended. The fact that devel opment is orchestrated by the growing point or, more precisely, by the shoot apical meristem, suggests that dormancy is also a property of the growing point. Understanding dormancy in terms of suspended develop ment requires the identification of events that are essential in develop ment, but lacking in dormancy. Essential in the developmentally active meristem is that the behaviour of individual cells is integrated by the continuous exchange of correlative signals. Certain signals cross the plasma membrane and the cell walls, whereas other signals traffic via plasmodesmata, which are abundant in all cell walls. Signalling via both pathways is essential for meristem functioning. Recent findings show that during the onset of photoperiodically induced dormancy in birch the meristem cells become uncoupled from their cooperatively generated
Paivi L. H. Rinne is Senior Scientist, and Christiaan van der Schoot is Professor, Plant Developmental Physiology, Department of Biology and Nature Conservation, Agricultural University of Norway, N-1432 As, Norway.
