Investigation of Plant Surfaces with Environmental Scanning Electron Microscopy (ESEM®) - A Comparison with Conventional SEM

Abstract

Environmental scanning electron microscopy (ESEM) enables the investigation of untreated and watercontaining material without preparation with the benefit of SEM (depth of focus and three dimensional imaging of surfaces with a high resolution). Conventional SEM (CSEM) usually requires time consuming fixation, drying and coating of samples. Their surface structures may be altered by this procedure. For comparison a large number of plant samples was observed with both methods. Using CSEM, secretion products or mucilagineous coatings may be removed and dynamic processes cannot be observed. However, the samples can be investigated several times. In contrast, ESEM allows the observation of watercontaining, native surfaces and this method is the only possibility to watch dynamic processes in the SEM. However, using ESEM the plant material is very sensitive to beam damages because of the lack of the protecting metall layer - necessary for non-conducting surfaces in CSEM and dehydration cannot be prevented completely. In summary, ESEM will not compete with CSEM but it will establish oneself as a valuable and essential supplement in studying plant surfaces.