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Mechanism of Cu~(2+) inhibiting photosynthesis of Spirulina maxima

Li Jianhong, Tai Zihou, Zeng Zhaoqi

Department of Biology Science and Biotechnology, Nanjing University. Nanjing 210093, Jiangsu； China

Abstract

In the paper, the authors studied the effects of Cu~(2+) on the growth and photosynthesis of blue green algae Spirulina maxima, and on the phycobilisomes(PBS) by absorption spectrum and fluorescence spectrum. These results showed that the concentrations of Cu~(2+) inhibiting algal growth and algal photosynthetic oxygen evolution were 10 #mu#mol L~(-1) and 150 #mu#mol　L~(-1) ， respectivly. Cu~(2+) also decreased the characteristic light absorption density of PBS (Fig.3). The changes of fluorescence intensities of PBS caused by different Cu~(2+) concentrations were observed (Fig.4). These results indicated that the PBS was a site of Cu~(2+) acting on. In vitro, Cu~(2+) could denature phycocyanin (PC) and decrease its visible light absorption peak , fluorescence peak and degree of fluorescence polarization . However, allophycocyanin (APC) was insensitive to Cu~(2+). The results suggested that Cu~(2+) acts on PC of PBS and inhibits light absorption and transmission of PBS.

Key words: Spirulina maxima;Copper ion;Phycobiliprotein;Photosynthesis

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Citing This Article：

Li Jianhong, Tai Zihou, Zeng Zhaoqi. Mechanism of Cu~(2+) inhibiting photosynthesis of Spirulina maxima. Acta Physiol Sin 1997; 49 (1): (in Chinese with English abstract).