Anatomy and ultrastructure of osmophores of Cymbidium tracyanum Rolfe (Orchidaceae)

The intense smell secreted by flowers of Cymbidium tracyanum Rolfe (Orchidaceae) derives from osmophores situated on the axipetal surface, mainly at the petals' base and the margin of labellum. The epiderm in those places created vesicular or somewhat elongated glandular cells, particularly on the labellum. In the production of smell 2-3 layers of subepidermal cells also take part. Submicroscopic examinations showed that those cells were characterized by the presence of a big nucleus. There were also numerous granules of starch and plastoglobules in plastids, a great amount of mitochondria and smooth-surfaced endoplasmic reticula. The traces of secretion products are visible on the surface of glandular cells. The above mentioned features are typical for osmophore cells.