Abstract
Sputtering is an easy, rapid and effective method for metal coating of pollen grains for examination in the scanning electron microscope. A very thin, regular and stable metal layer is obtained by bombarding a metal target with ions under a low vacuum, so that it ejects atoms on to the specimen. This allows of the observation of exine sculpturing which would be completely masked by a coating resulting from evaporation of carbon and metal. The sputtering method was tested on pollen of Deschampsia flexuosa, Molinia caerulea and Betula pubescens. Very narrow perforations could be discerned in the exine, similar to those seen in the images of carbon replicas obtained by many authors with the transmission electron microscope.