Abstract:The free radicals in snow algae Chlamydomonas nivalis were determined using 2’, 7’-dichlorodihydrofluorescin diacetate (DCFH-DA) as fluorescence probe. In the cell, DCFH-DA was hydrolyzed to 2’, 7’-dichlorodihydrofluorescin (DCFH), and then quickly oxidized to fluorescent compound 2’, 7’-dichlorofluorescin (DCF). The quantity of oxidation was in direct proportion to the content of free radicals. For the determination of free radicals by fluorescence spectrophotometer, the best dosage of DCFH-DA, cell counts and reaction time were 60μmol/L, 5×106~20×106 cell/mL and 1~2.5 h, respectively. And the best excitation and emission wavelength were 485 nm and 520 nm, respectively. Under those conditions, the free radicals in algae can be stably and rapidly determined.
