Effects of different concentrations of copper ion on the growth and chlorophyll fluorescence characteristics of Scendesmus obliquus L.

Algae, live in body of water, are inevitably stressed by copper pollution. The growth and chlorophyll fluorescence traits of Scendesmus obliquus exposed to the culture medium (BG11) with different copper concentration for different times (12, 24, 36 and 48 h) were studied. The main parameters determined in the study included the maximal photochemical efficiency of PSⅡ (Fv/Fm), the actual photochemical efficiency of PS Ⅱ in the light (ΦPSⅡ=yield), the potential activity of PSⅡ ( Fv/Fo), the maximal relative electron transport rate (Pm, rETRmax), light use efficiency(α), cell density (A650nm), chlorophyll a, chlorophyll b and carotenoid contents. The results showed that the main parameters including Fv/Fm, ΦPSⅡ , Fv/Fo, rETR, α and cell density were decreased significantly with the increase of copper-ion concentrations and the prolongation of time. The concentrations of the chlorophyll a, chlorophyll b and carotenoid showed the similar changing trend, however, when the copper-ion concentrations were low, the tendency was not significant. Therefore, the high content of Cu2+ (40~100 μmol·L-1) inhibited the growth and chlorophyll fluorescence of Scendesmus obliquus severely, but the low copper contentration (0~10 μmol·L-1) did not affected the growth and chlorophyll fluorescence of Scendesmus obliquus significantly.