A Structural Study of the Floral Epidermal Hairs of Digitalis purpurea Using Light, Electron and X-ray Microscopy

In Digitallis purpurea the cytoplasm of the floral trichomesof mature flowers, when examined by light microscopy, appearsto be located centrally and arranged as discrete cytoplasmicstrands. Such strands are not apparent when viewed by electronmicroscopy, rather the cytoplasm is mainly peripheral with alarge central vacuole. In younger flowers, before corolla opening,the cytoplasm appears to be more abundant as seen in electionmicrographs and in places occupies the centre of the cell, butit is always highly vesiculated and without the high degreeof structural organization seen by light microscopy. Soft X-ray contact microscopy is a relatively new techniquewhich still requires considerable development if it is to bewidely used by biologists. The present study shows, however,that the images obtained of the cytoplasm are possibly morefaithful to the arrangement in the original, living materialthan those obtained by electron microscopy, since the transcellularstrands and associated organelles are clearly imaged. As suchthe technique is a very useful technique complementary to conventionalmicroscopical methods. Trichrome, ultrastructure, Digitalis, X-ray microscopy