Acid-Fastness of pine pollen

This is a study of the acid-fast staining characteristics of pine pollen and an investigation of factors causing loss of acid-fastness after pine pollen has been in contact with tisues or mucous membranes. Intact loblolly pine pollen was readily stained with cold carbol-fuchsin, and retained its acid-fastness after decolorization with 3% HC1 in 95% ethyl alcohol for 2 min, followed by methylene blue counterstain. Pine pollen resembles spermatozoa in ease of staining and resistance to decolorization. Acid-fastness was destroyed by crushing or by germination of the pollen grain, and by contact for several hours with serum or saline solutions, but was unchanged by exposure to 0.1% solution of streptomycin in water. Nonviable pine pollen did not lose acid-fastness after suspension for several days in serum or water. When counterstain was omitted, crushed or germinated pollen appeared red to pink after staining with carbol-fuchsin and decolorization with acid alcohol, thus indicating that lipids of an acid-fast nature were still present. The large size and biologic properties of pine pollen provide a unique means of studying the chemical and physical aspects of the acid-fast phenomenon.