Effects of heavy metals ions on primary photosynthetic processes in Antarctic filamentous alga Zygnema sp. ( Short Communication )

Abstract

Algae show different extent of resistance to heavy metals. In this study, the resistance of green filamentous alga Zygnema sp. (strain EEL201, originally collected at James Ross Island, Antarctica) was tested by chlorophyll fluorescence parameters. The alga was taken from the stock culture cultivated on agar, innoculated to liquid medium and allowed to develop biomass large enough for exposition experiments. Heavy metal treatments consisted of addition of Cd and Zn so that effective concentration was 66 mM. Response of primary photosynthetic processes to Cd, Zn addition was assessed by the exposition time-dependent decrease in potential quantum yield (FV/FM) photosystem II (PS II) and relative fluorescence decline ratio (RFd). Cd- and Zn-treated Zygnema sp. exhibited similar extent of decline of the two parameters associated with inhibition of primary processes of photosynthesis. Negative changes to PS II, however, did not bring full inhibition of PS II functioning since FV/FM was about 0.450 after 120 min. exposition. The results might indicate a potential of Antarctic Zygnema in the studies focused on resistance to heavy metals and phytoremediation technologies.