US EPA

3109620 

Journal Article 

Toxic effects of mercury on PSI and PSII activities, membrane potential and transthylakoid proton gradient in Microsorium pteropus 

Deng, C; Zhang, D; Pan, X; Chang, F; Wang, S 

2013 

1 

Journal of Photochemistry and Photobiology B: Biology
ISSN: 1011-1344
EISSN: 1873-2682 

127 

1-7 

English 

23920143 

10.1016/j.jphotobiol.2013.07.012 

WOS:000326767000001 

Mercury (Hg) is one of the top toxic metals in environment and it poses a great risk to organisms. This study aimed to elucidate the toxic effects of Hg2+ on energy conversion of photosystem I (PSI) and photosystem II (PSII), membrane potential and proton gradient of Microsorium pteropus (an aquatic plant species). Contents of chlorophyll a, chlorophyll b and carotenoids, quantum yield and electron transfer of PSI and PSII of M. pteropus exposed to various concentrations of Hg2+ were measured. With increasing Hg2+ concentration, quantum yield and electron transport of PSI [Y(I) and ETR(I)] and PSII [Y(II) and ETR(II)] decreased whereas limitation of donor side of PSI [Y(ND)] increased. At >= 165 mu g L-1 Hg2+, quantum yield of non-light-induced non-photochemical fluorescence quenching in PSII [Y(NO)] significantly increased but quantum yield of light-induced non-photochemical fluorescence quenching [Y(NPQ)] decreased. Membrane potential (Delta psi) and proton gradient (Delta pH) of M. pteropus were reduced significantly at 330 mu g L-1 Hg2+ compared to control. Mercury exposure affected multiple sites in PSII and PSI of M. pteropus. (C) 2013 Elsevier B.V. All rights reserved. 

Photosystem I; Mercury; Membrane potential; Proton gradient; Aquatic plant