Silva Fennica : quarterly issues : 35(1) : sa351111.htm
Effect of accumulated duration of the light period on bud burst in Norway spruce (Picea abies) of varying ages
Silva Fennica 35(1): 111–117
One-year-old seedlings (two sowing times), two-year-old seedlings and 14- and 18-year-old cuttings of Norway spruce (Picea abies (L.) Karst.) were exposed to shortening photoperiod (initially 16 h), lengthening photoperiod (initially 6 h) and constant short photoperiod (6 h) treatments with uniform temperature conditions in growth chambers. The timing of bud burst was examined. In all plants, shortening photoperiod treatment seemed to promote bud burst compared with other treatments. This effect was clearest in the oldest material. The results suggest that, in addition to temperature sum, the accumulated duration of the light period may promote bud burst of Norway spruce.
Keywords
growth initiation, phenology, photoperiod, Norway spruce
Addresses
Partanen, Finnish Forest Research Institute, Punkaharju Research Station, Finlandiantie 18, FIN-58450 Punkaharju, Finland; Leinonen and Repo, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland. Fax +358 15 644 333, E-mail jouni.partanen@metla.fi
Received 16 November 1999 Accepted 18 January 2001
ISSN 0037-5330