Fluorescence Microscopy in the Study of Pollen Grains and Pollen Tubes

Fresh pollen gains were either crushed directly in a 0.01% solution of acridine orange (0.1 M phosphate-citrate buffer, pH 5.2-5.4) or they were germinated previously in 5-25% sucrose solution (glass-distilled water of pH 5.0-6.0 with 100 ppm H₃BO₃) inside moist incubating chambers at 24-30° C. Observations and records were made by using ultraviolet or blue-violet light with suitably coupled exciter and barrier filters. When the pollen grains, tube walls or cytoplasm interfered with observation of a particular cell content, the same was either pressed or dissected out of the gain or the tube. The vegetative, generative or sperm cells as well as other protoplasmic contents, such as plastid-like bodies, lipid granules and mitochondria could be differentiated.