Anatomical Changes and Peroxidase Activity After Cytokinin Treatments Inducing Adventitious Bud Formation on Embryos of Picea abies

Abstract

Adventitious buds were initiated on embryos of Picea abies (L.) Karst. after a pulse treatment with benzyladenine (BA). The embryos released cytokinin-like substances into the culture medium for 16 h after pulse treatment. When embryos were cultured on medium containing the cytokinin-like substances for more than 6 days, elongation of cotyledons and roots was inhibited, and a meristematic layer was formed from epidermal and subepidermal cells. Meristematic centers and adventitious buds subsequently developed from this layer. In embryos transferred to fresh culture medium after the initial release of cytokinin-like substances, cotyledons and roots elongated to various extents. Frequency of cell division increased after the BA treatment, but no meristematic layer was formed. A few localized cell divisions in epidermal and subepidermal cells led to the organization of discrete meristematic centers from which adventitious buds subsequently developed. The developmental pattern for meristematic centers, the tim...