Suspensor Development in Gagea Lutea (L.) Ker Gawl., with Emphasis on the Cytoskeleton

The study used fluorescence microscopy to examine changes in cytoskeleton configuration during development of the embryo suspensor in Gagea lutea and to describe them in tandem with the development of the embryo proper. During the early phase of embryo suspensor development, tubulin and actin filaments were observed in the cytoplasm of the basal cell from the micropylar to the chalazal ends of the cell. Around the nucleus of the basal cell were clusters of numerous microtubules. These accumulations of tubulin arrays congregated near the nucleus surface; numerous bundles of microtubules radiated from the nucleus envelope. At this time, microfilaments formed a delicate network in the cytoplasm of the basal cell. In the fully differentiated embryo suspensor, microtubules were observed at the chalazal end of the basal cell. Numerous bundles of microtubules were visualized in the cytoplasm adjacent to the wall separating the basal cell from the embryo proper. Microfilaments formed a dense network which uniformly filled the basal cell cytoplasm. There were some foci of F-actin material in the vicinity of the nucleus surface and at the chalazal end of the basal cell. In all studied phases of embryo suspensor development a prominent cortical network of actin and tubulin skeleton was observed in embryo proper cells.