low-temperature scanning electron microscopy

The preparation  of specimens for the scanning electron microscope, and their subsequent examination, at very low temperatures. The specimen is frozen with liquid nitrogen (the melting point of nitrogen is -210°C), coated at liquid nitrogen temperatures, and examined in a special specimen chamber similarly cooled. In this way frozen hydrated material can be examined. The results are similar to those obtained by *critical-point drying but with fewer artefacts. The technique is particularly useful for delicate plant specimens.