Distribution of Gibberellins and Abscisic Acid in Different Fruit Parts of Rye (Secale cereale L.). Gibberellins LXVII

Contents of free GAs and ABA during anthesis and fruit development were determined by bioassay and ORD measurement, respectively. Distribution of single GA components (GA8, GA16, neutral GA16 conjugate) and ABA in the embryo and the endosperm part of caryopses has been studied at 4 different stages. The free GAs are mainly located in the endosperm part, and the neutral GA16 conjugate occuring during milk ripeness was found in the embryo to a high extent. ABA has also been detected mainly in the endosperm part. Its level in the embryo was highest at milk ripeness, reaching about 16% of the ABA content of total fruit. Location of hormones in the fruit parts and alterations of hormone levels are discussed with respect to hormone function and sites of biosynthesis and metabolism.