Ecotype-dependent control of growth, dormancy and freezing tolerance under seasonal changes in Betula pendula Roth

摘要: Woody plants in the temperate and boreal zone undergo annual cycle of growth dormancy under seasonal changes. Growth cessation induction autumn are prerequisites for development substantial cold hardiness winter. During evolution, woody have developed different ecotypes that closely adapted to local climatic conditions. In this study, we employed distinct photoperiodic silver birch (Betula pendula Roth) elucidate differences these adaptive responses all ecotypes, short day photoperiod (SD) initiated development, induced acclimation. Subsequent low temperature (LT) exposure significantly enhanced freezing tolerance but removed bud dormancy. Our results suggested might partially overlap SD, two processes were regulated by mechanisms pathways LT. Endogenous abscisic acid (ABA) levels also altered changes; ABA level was during growing season, then increased autumn, decreased Compared with southern ecotype, northern ecotype more responsive changes, resulting earlier cessation, acclimation higher faster release winter, flush initiation spring. addition, although there no significant ecotypic difference rates degrees alterations between could be related tolerance.