The use of cetylpyridinium chloride to preserve water-soluble surface material in pollen for electron microscopy

During fixation of an allergenic pollen (Corylus avellana) the addition of cetylpridinium chloride (CPC) to the buffered glutaraldehyde led to the preservation of specific material which was lacking after fixation in glutaraldehyde alone. CPC-reactive substances form a distinct covering layer around the pollen grains, but they also occur within the baculoid region of the sexine and the spherosomes of the cytoplasm. In a non-allergenic pollen (Pinus mugo) no CPC-reactive material was found. A chemical similarity between the acid mucopolysaccharides precipitated by CPC in animal connective tissue and the material stained in pollen must be assumed. The possible importance of the visualized substances as to their role as allergens is briefly discussed.