Protocol for Preparation of Samples of Desmids (Desmidiaceae, Zygnematophyceae) for Morphological Studies using Scanning Electron Microscopy

ABSTRACT

Scanning electron microscopy (SEM) is a robust tool in the study of desmids (Desmidiaceae, Zygnematophyceae), assisting in the interpretation of ornamentation on the cell wall, in view of its use as a taxonomic feature. Despite this, it is not always easy to obtain a good processing of the material for analysis in SEM, due to problems with mucilage present in the cells, obtaining representative material in the stub, and dehydration time. Therefore, we adapted an inexpensive protocol, with no cell distortion and fast processing (two days) for analysis under SEM. The material was obtained from samples fixed in Transeau solution, washed with cetyltrimethylammonium bromide to remove mucilage from the cells, concentrated in a coverslip used with Poly-L-lysine as an adhesive, and dehydrated in a gradual series of Acetone. The results are compared with other studies carried out in the group.

Keywords:
cell wall ornamentation; desmidiaceae; freshwater algae; microscopy; ultrastructure