Cryofixation of Plant Material for Ultrastructura1 and Analytical Studies

Studies (1—4) have shown that high-molecular weight, water soluble polymers such as polyvinylpyrrolidone (PVP) and hydroxyethyl starch (HES) are useful in reducing ice-crystal damage in rapidly frozen samples of plant and animal tissues as judged by their appearance in freeze-etch replicas, frozen sections, and frozen fracture faces of bulk material. We have extended these studies to the preparation of material for correlative ultrastructural and analytical studies where it is important both to retain diffusible elements in their natural position in cell as well as preserving adequate cell morphology.