| Abstract: | Epon 812 was used successfully as an embedding medium for the preparation of the secondary meristem and its derivatives in Pinus radiata for light microscopy. Specimens were fixed in glutaraldehyde followed by osmium tetroxide solution, using a schedule developed for the electron microscopy of these tissues. Sections from 2 to 5 μm thick were cut using an LKB Ultratome III and glass knives. Sections were evaluated without prior removal of the embedding medium using bright-field, phase-contrast and interference-contrast microscopy. Results for cambium were generally superior to those obtained by using the conventional fixatives for light microscopy and paraffin embedding. The advantages and disadvantages of this technique are discussed and it is concluded that the use of Epon for embedding this type of material is easier and gives better results than older established methods. It is suggested that methods of electron microscopy be considered when the preparation of a material for light microscopy has proved difficult or impossible by other means, or when particularly thin sections are required. |
