UTILIZATION OF SEM AND FREEZE-ETCH TECHNIQUES IN THE STUDY OF HYPNOSPORES.

Hypnospores, a type of sculptured-walled resting spore formed by some zoosporic chlorophycean and chrysophyccan algae, have been viewed at the ultrastructural level using thin section, SEM, and freezetech techniques. The "spiny" wall of the hypospore, as seen in the light microscope, appears as a raised, scalloped surface at the ultrasturctural level. The PAS-positive wall is composed of 2 distinct layers. Prior to the formation of the wall, vacuoles form in the cytoplasm, lipid deposits are detectable, and typical cytoplasmic organelles appatently degenerate. The entire process is completed in less than 24 hr. [ABSTRACT FROM AUTHOR]