The abscisic acid content of dormant birch buds

摘要

Abscisic acid (ABA) has been identified in the buds and xylem sap ofBetula verrucosa(Ehrh.). Buds also contain esterified ABA. In the course of the winter the proportion of esterified ABA in the buds undergoes a progressive increase which may be associated with emergence from dormancy.