%A Du Lin fang, Fu Hua long and Zou Xiao dong %T Effect of Cu2+ on PSⅡ Activity and Energy Transfer of Phycobillisome in Intact Cells of Spirulina platensis %0 Journal Article %D 1995 %J J Integr Plant Biol %R %P -${article.jieShuYe} %V 37 %N 2 %U {https://www.jipb.net/CN/abstract/article_23747.shtml} %8 %X Addition of Cu2+ at low concentrations, to intact cells of the cyanobacterium, Spirulina platensis, at room temperature, caused an enhancement in intensity of fluorescence emitted by phycocyanin and induced a blue shift at the emission peak, both of which indicated changes in energy transfer within the phycobillisomes. Cu2+ also suppressed the whole-chain electron transport activity (H2O→MV) and water-splitting activity of the photosystem Ⅰ. When isolated phycocyanin and allophycocyanin were exposed to very low concentrations of Cu2+ ions, C-phycocyanin but not allophycocyanin, exhibited decrease not only in the absorbance in the longer wavelength (616--620 nm) region, but also in the fluorescence emission intensity at 647 nm accompanied by a blue shift to 643 nm. These results suggested that Cu2+ selectively bleach C-phycocyanin.