Shoot Apical Meristems of Picea sitchensis Seedlings Accelerate in Growth Following Bud-set

First-year seedlings of Picea sitchensis were induced to setbuds by transferring them from long days (17 h) to short days(10 h at 20 °C, 12 h night at 12 °C). After 20 shortdays, the seedlings stopped growing in height, the shoot apicaldomes began enlarging and the transverse growth rates of theshoot apical dome tissues increased. For about 25 days thereafterprimordia were produced faster within the developing buds thanat the apices of seedlings which had been kept in long daysto prevent bud-set. Accelerated primordia production after bud-setenables the largest possible buds to be formed during the frost-freeperiod before winter. Picea sitchensis, apical meristem, bud-set