Sem-observation of developing plant organs using deep-frozen specimens

The SEM-observation of plant material normally requires dehydrated, dry specimens coated with carbon or metal. Unfortunately, the standard drying methods (including the critical-point-drying-technique) often cause shrinking and deformation of the specimen surface; therefore, SEMstudies on plant ontogeny are rather difficult, material- and time-consuming. Experiments using deep-frozen specimens have been carried out in England and in the USA, but have proved not satisfying. Recently, a new preparation technique working with shock-frozen specimens has been developed by ALDRIAN at the Technical University of Graz (Austria). This technique, originally devoted to checking the water content of concrete, was tested and applied to living plant material by the present communicators. As a test object the Malayan gesneriad Monophyllaea horsfieldii was chosen. Studying in special the inflorescence and calyx development, the results proved by far superior to those obtained by conventional SEM-preparation methods. As it appears this technique can be successfully employed in ontogenetical and morphological studies of any kind working with living material.