ABSTRACT
Growth cessation is a prerequisite for dormancy and rest. This chapter shows that the very different behavior of the two species: Pinus sylvestris and Picea abies. Under natural conditions, Pinus sylvestris, as well as Picea abies, develops rest. Successive prolongation of the night with 1 h/week has proven to give resting buds in Pinus sylvestris at different night lengths, depending on the origin of the seedlings. The results are taken from an experimental series with the aim of studying the influence of conditions provided throughout the development of seedlings of different origin on the development of dormancy, autumn frost hardiness, and resistance to frost drought. Conditions adjusted to the demands of Pinus sylvestris and to the demands of Picea abies have been used to raise seedlings of both species. In both species, autumn frost hardiness, as well as resistance to frost drought, were better in seedlings of the northern provenance than in the southern one.
