Cryo-planing for cryo-scanning electron microscopy (SEM) - a method for observation of xylem contents in Rosa stems.

摘要

A sample preparation technique for low temperature scanning electron microscopy, called cryo-planing for cryo-scanning electron microscopy (Cryo-SEM) is described. Successful cryo-planing required a stable attachment of the specimen to a holder. Clamping with a screw mechanism and using indium as space filler sufficed for 3 cryo-planing methods studied, i.e. cryo-milling, microtomy in a cold room and cryo-ultramicrotomy. From the 3 methods, the latter one was preferred. A small modification of this cryo-planing method using cryo-ultramicrotomy was then applied for a series of Cryo-SEM observations. The results showed that the cryo-ultramicrotomy technique enables observations of flat sample surfaces of frozen, fully hydrated plant specimens such as stems of ornamental flowers (roses and chrysanthemums), but also for Cryo-SEM observations of hazel stems, other plant materials such as rapeseed pistils and even dermatological research samples. The cryo-ultramicrotomy technique can be applied successfully to improve observations from cryo-SEM specimen, enhance results from x-ray microanalysis and enhance results from (digital) image analysis. The planing method can be applied on fibrous, hard and delicate materials as well.