Structure and development of vegetative buds, from the lower crown of Picea abies

Abstract

Seasonal changes in the development of Norway spruce (Picea abies (L) Karst) vegetative buds in the lower crown position of 4 18-year-old free standing grafts in the climatic conditions of Poland are described. Bud awakening varies with the season while the end of shoot elongation, after about 6 weeks, seems to be weather independent. Mitotic activity of the embryonic shoot starts about 1 month before bud-burst. The new winter bud develops in 2 periods of bud scale primordia initiation (autumn and spring) and 1 period of needle primordia initiation (during summer). The curves of apical dome size (width and height) have 2 peaks: the 1st one, in late April just before the 1st spring bud scale primordium emerges, and the 2nd one, during the time of rapid needle initiation (mid-August). There is seasonal variation in starch accumulation. Starch is absent in the dormant bud. In the developing bud, starch is associated with areas of high morphogenic activity. © 1995 Elsevier/INRA.