staining P. expansum spores with or without NaHCO3 treatment were collected after 2 to 10 h incubation. Then, the spores were stained by 20 g/mL prodium iodide or 50 g/mL 4,6-diamidino-2-phenylindole (DAPI) for 30 min at 30◦C in dark. After centrifugationand repeated washing with phosphate buffer solution (pH 7.4) toremove residual dye,