Toxic effects of mercury on PSI and PSII activities, membrane potential and transthylakoid proton gradient in Microsorium pteropus.
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 Hg(2+) 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 Hg(2+) were measured. With increasing Hg(2+) 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 ⩾165μgL(-1) Hg(2+), 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 (Δψ) and proton gradient (ΔpH) of M. pteropus were reduced significantly at 330μg L(-1) Hg(2+) compared to control. Mercury exposure affected multiple sites in PSII and PSI of M. pteropus.
Key Lab of Plateau Lake Ecology & Global Change, College of Tourism and Geographic Science, Yunnan Provincial Key Laboratory of Plateau Geographical Process and Environmental Change, Yunnan Normal University, Kunming 650500, China; Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China.
Chunnuan
C
Deng
Daoyong
D
Zhang
Xiangliang
X
Pan
Fengqin
F
Chang
Shuzhi
S
Wang
D001692:Biological Transport; D004579:Electron Transport / Q000187:drug effects; D004734:Energy Metabolism / Q000187:drug effects; D004785:Environmental Pollutants / Q000378:metabolism / Q000633:toxicity; D006863:Hydrogen-Ion Concentration; D008564:Membrane Potentials / Q000187:drug effects*; D008628:Mercury / Q000378:metabolism / Q000633:toxicity*; D045331:Photosystem I Protein Complex / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D010860:Pigments, Biological / Q000378:metabolism; D011522:Protons; D013312:Stress, Physiological / Q000187:drug effects; D020524:Thylakoids / Q000187:drug effects*; D064028:Tracheophyta / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology
D004785:Environmental Pollutants; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D010860:Pigments, Biological; D011522:Protons; D008628:Mercury
Aquatic plant; Membrane potential; Mercury; Photosystem I; Proton gradient