ULTRASTRUCTURE AND SECRETION OF THE SECRETORY-CELLS OF 2 SPECIES OF FAGONIA L. (ZYGOPHYLLACEAE)

The ultrastructure and secretion of the secretory cells of the glandul ar trichomes of Fagonia mollis and F. glutinosa were studied. The most important finding of this study is that two species of the same genus produce the lipophilic component of the secretory material in complet ely different ways and at different sites within the cell. In the earl y stages of development of secretory cells of F. mollis, numerous mito chondria, containing myelin-like structures, occur in the basal part o f the cell. Above them, highly-elongate elements, which are suspected to develop from mitochondria with myelin-like structures, are present. These have been termed 'modified mitochondria'. It is suggested that the myelin-like structures are precursors of the lipophilic material o f F. mollis. In F, glutinosa, the lipophilic material appears first in the plastids as plastoglobuli. Polysaccharides appear to be produced by dictyosomes in both species. Secretion of the secretory substance t o the outside of the protoplast appears to be granulocrine. (C) 1998 A nnals of Botany Company.