Ultrastructure and secretion of the secretory cells of two species of Fagonia L. (Zygophyllaceae)

Abstract

The ultrastructure and secretion of the secretory cells of the glandular 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 completely different ways and at different sites within the cell. In the early stages of development of secretory cells of F. mollis, numerous mitochondria, containing myelin-like structures, occur in the basal part of 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 of 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 to the outside of the protoplast appears to be granulocrine.