THE PLASTIDS OF THE YEW TREE (TAXUS-BACCATA L) - ULTRASTRUCTURE AND IMMUNOCYTOCHEMICAL EXAMINATION OF CHLOROPLASTIC ENZYMES

The various types of plastids occurring in assimilatory and non-green tissues of Taxus baccata L. were investigated with respect to their ultrastructure and their content of starch, chlorophyll, Rubisco and the plastidic coupling factor CF1. Chlorophyll was estimated from fluorescence intensity, and the presence of both enzymes was examined by electron microscopy after immunogold labelling. All kinds of plastids, irrespective of their location in the tree, contained stromal membranes. Due to their content of CF, and chlorophyll (except those of the roots) these membranes were addressed as thylakoids. Since the plastids also contain Rubisco, they represent chloroplasts. However, a decreasing gradient of all investigated chloroplastic characters from the plastids of the assimilatory tissue of the needles to those of axial tissues and of the roots was obvious. All kinds of plastids accumulated large amounts of starch especially in spring prior to bud burst but were virtually free of starch during the winter months.