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Inhibition of Photosystem II in the Green Alga Ankistrodesmus falcatus by Copper
Author(s) -
SHIOI YUZO,
TAMAI HIROKO,
SASA TSUTOMU
Publication year - 1978
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1978.tb01651.x
Subject(s) - photosystem ii , dcmu , copper , chemistry , hill reaction , photochemistry , oxidizing agent , electron transport chain , photosynthetic reaction centre , nuclear chemistry , photosystem i , light intensity , photosynthesis , inorganic chemistry , electron transfer , biochemistry , organic chemistry , chloroplast , physics , optics , gene
Copper strongly inhibited 2,6‐dichloroindophenol (DCIP) photoreduction in the broken cells of the green alga Ankistrodesmus falcatus (C303), and the activity lost could not be restored by adding 1,5‐diphenylearbazide (DPC). Inactivation of the DCIP Hill reaction reached 45% after incubation with 10 μ M cupric sulfate for 20 min. In the same time, copper (13 μg/mg chlorophyll) was bound to the broken cells. Addition of 10 m M KCl reduced copper binding by about 53%. Fluorescence intensity at room temperature decreased upon addition of cupric sulfate and was partially restored by adding 3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea (DCMU), These results suggest that copper inactivates electron transport between the oxidizing side of the reaction center of photosystem II and the electron‐donating site of DPC. Further, the effect of light intensity shows that copper mostly affected the reaction rate of the dark step and had less inhibitory effect on the quantum efficiency of the primary reaction of electron transport in photosystem II.